Precluding Useless Events for On-Line Global Predicate Detections

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错误与遗漏条款英语作文

错误与遗漏条款英语作文Title: Errors and Omissions Clause in Contracts。

In the realm of legal contracts, an Errors and Omissions (E&O) clause plays a pivotal role in defining the responsibilities and liabilities of parties involved. It serves as a protective measure against potential misunderstandings, mistakes, or omissions that may occur during the execution of contractual obligations. This essay delves into the significance of the Errors and Omissions clause, its components, and its implications in contractual agreements.The Errors and Omissions clause, often included in professional service contracts, insurance policies, and other agreements, serves to mitigate risks associated with inaccuracies, oversights, or failures to perform as expected. This clause typically outlines the following key aspects:1. Scope of Coverage: The clause delineates the scope of errors and omissions covered under the contract. It specifies the types of errors or omissions that the party will be held liable for, ensuring clarity regarding the extent of protection provided.2. Standard of Care: It establishes the standard of care expected from the parties involved. This standard varies depending on the nature of the contract and the industry standards. For instance, a contract involving medical services would require a higher standard of care compared to a general consulting agreement.3. Notice Requirements: The clause often includes provisions regarding the notification process in case of errors or omissions. It may specify the timeframe within which the affected party must notify the other party of the error or omission to initiate the resolution process.4. Remedies and Damages: It outlines the remedies available to the aggrieved party in the event of errors or omissions. This may include corrective actions, such asreperformance of services, as well as provisions for indemnification or monetary damages to compensate for losses incurred.5. Limitation of Liability: The clause may include limitations on the liability of the parties, such as caps on monetary damages or exclusions for certain types of losses. These limitations aim to protect the parties from excessive financial exposure while still ensuring accountability for errors and omissions.6. Dispute Resolution: In some cases, the clause may specify procedures for resolving disputes arising from errors or omissions, including methods such as mediation, arbitration, or litigation.7. Insurance Requirements: Depending on the nature of the contract, the clause may require one or both parties to maintain professional liability insurance to coverpotential errors and omissions.Implementing an Errors and Omissions clause incontracts offers several benefits for all parties involved. Firstly, it helps to clarify expectations and responsibilities, reducing the likelihood of disputes arising from misunderstandings. Secondly, it provides a framework for addressing errors and omissions in a systematic manner, facilitating prompt resolution and minimizing disruptions to the project or service. Additionally, it serves as a form of risk management, allowing parties to anticipate and mitigate potential liabilities.However, it's essential to draft the Errors and Omissions clause carefully to ensure its effectiveness and enforceability. Ambiguous language or inadequate coverage could lead to disputes and legal challenges down the line. Therefore, parties should seek legal counsel to tailor the clause to their specific needs and circumstances, taking into account relevant laws and industry practices.In conclusion, the Errors and Omissions clause is a vital component of contractual agreements, offering protection against the risks inherent in professionalservices and other business transactions. By clearly defining rights, obligations, and remedies related to errors and omissions, this clause helps to foster transparency, accountability, and trust between parties. As such, it deserves careful consideration and attention during the contract drafting process to safeguard the interests of all stakeholders involved.。

tpo32三篇托福阅读TOEFL原文译文题目答案译文背景知识

tpo32三篇托福阅读TOEFL原文译文题目答案译文背景知识阅读-1 (2)原文 (2)译文 (5)题目 (7)答案 (16)背景知识 (16)阅读-2 (25)原文 (25)译文 (28)题目 (31)答案 (40)背景知识 (41)阅读-3 (49)原文 (49)译文 (53)题目 (55)答案 (63)背景知识 (64)阅读-1原文Plant Colonization①Colonization is one way in which plants can change the ecology of a site.Colonization is a process with two components:invasion and survival.The rate at which a site is colonized by plants depends on both the rate at which individual organisms(seeds,spores,immature or mature individuals)arrive at the site and their success at becoming established and surviving.Success in colonization depends to a great extent on there being a site available for colonization–a safe site where disturbance by fire or by cutting down of trees has either removed competing species or reduced levels of competition and other negative interactions to a level at which the invading species can become established.For a given rate of invasion,colonization of a moist,fertile site is likely to be much more rapid than that of a dry, infertile site because of poor survival on the latter.A fertile,plowed field is rapidly invaded by a large variety of weeds,whereas a neighboring construction site from which the soil has been compacted or removed to expose a coarse,infertile parent material may remain virtually free of vegetation for many months or even years despite receiving the same input of seeds as the plowed field.②Both the rate of invasion and the rate of extinction vary greatly among different plant species.Pioneer species-those that occur only in the earliest stages of colonization-tend to have high rates of invasion because they produce very large numbers of reproductive propagules(seeds,spores,and so on)and because they have an efficient means of dispersal(normally,wind).③If colonizers produce short-lived reproductive propagules,they must produce very large numbers unless they have an efficient means of dispersal to suitable new habitats.Many plants depend on wind for dispersal and produce abundant quantities of small,relatively short-lived seeds to compensate for the fact that wind is not always a reliable means If reaching the appropriate type of habitat.Alternative strategies have evolved in some plants,such as those that produce fewer but larger seeds that are dispersed to suitable sites by birds or small mammals or those that produce long-lived seeds.Many forest plants seem to exhibit the latter adaptation,and viable seeds of pioneer species can be found in large numbers on some forest floors. For example,as many as1,125viable seeds per square meter were found in a100-year-old Douglas fir/western hemlock forest in coastal British Columbia.Nearly all the seeds that had germinated from this seed bank were from pioneer species.The rapid colonization of such sites after disturbance is undoubtedly in part a reflection of the largeseed band on the forest floor.④An adaptation that is well developed in colonizing species is a high degree of variation in germination(the beginning of a seed’s growth). Seeds of a given species exhibit a wide range of germination dates, increasing the probability that at least some of the seeds will germinate during a period of favorable environmental conditions.This is particularly important for species that colonize an environment where there is no existing vegetation to ameliorate climatic extremes and in which there may be great climatic diversity.⑤Species succession in plant communities,i.e.,the temporal sequence of appearance and disappearance of species is dependent on events occurring at different stages in the life history of a species. Variation in rates of invasion and growth plays an important role in determining patterns of succession,especially secondary succession. The species that are first to colonize a site are those that produce abundant seed that is distributed successfully to new sites.Such species generally grow rapidly and quickly dominate new sites, excluding other species with lower invasion and growth rates.The first community that occupies a disturbed area therefore may be composed of specie with the highest rate of invasion,whereas the community of the subsequent stage may consist of plants with similar survival ratesbut lower invasion rates.译文植物定居①定居是植物改变一个地点生态环境的一种方式。

上海市风华中学2024-2025学年高三上学期9月阶段测试英语试题

上海市风华中学2024学年度第一学期高三年级英语阶段测试（2024.9）（满分140分考试时间：120分钟）第Ⅰ卷I. Listening ComprehensionSection A 10%Directions: In Section A, you will hear ten short conversations between two speakers. At the end of each conversation, a question will be asked about what was said The conversations and the questions will be spoken only once. After you hear a conversation and the question about it, read the four possible answers on your paper, and decide which one is the best answer to the question you have heard.1. A. She has no appetite at all. B. She wants to dine out.C. She is too tired to go out.D. She prefers to cook at home.2. A. 6 pounds B. 7 pounds. C. 8 pounds. D. 9 pounds.3. A. At the professor's office. B. In the bookstore.C. In the library.D. In the laboratory.4. A. Because something went wrong with his car.B. Because his car was broken in an accident.C. Because he wanted to take a walk for a rest.D. Because he was stuck in a traffic jam.5. A. The morning flight. B. The afternoon flight.C. The evening flight.D. The midnight flight.6. A. She is not interested in going camping with him.B. She wants the man to stay at home with her.C. She thinks the man needs to have a good rest.D. She thinks the man should prepare for the exams.7. A. Some major revisions are needed. B. It should be revised by a tutor.C. Only a few changes should be made.D. The draft needs no revision at all.8 A. He is going away for a while. B. He worked hard to earn money.C. He did very well in the exam.D. He can't wait to have a rest.9. A. He forgot to bring his own camera. B. He is not good at taking pictures.C. He cannot take a photo with the camera.D. He doesn't know how to use the camera.10. A. She was interrupted by a visiting friend. B. She didn't come back until midnight.C. She stayed up late for the final exam.D. She visited her friend instead of studying.Section BDirections: In Section B, you will hear two short passages, and you will be asked several questions on each of the passages. The passages will be read twice, but the questions will be spoken only once. When you hear a question, read the four possible answers on your paper and decide which one would be the best answer to the question you have heard.Questions 11 through 13 are based on the following passage.11. A. They can maintain their body temperature stable.B. They conserve enough energy before the long sleep.C. They can keep their heart beat at a regular rate.D. They have their weight increased to the maximum.12. A. By staying in bidıng places and eating little.B. By seeking extra food and warm shelter.C. By growing thicker hair to stay warm.D. By storing enough food in advance.13. A To stay safe. B. To save energy. C. To get more food. D. To protect the young. Questions 14 through 16 are based on the following passage.14. A. Four to six hours. B. Six to nine hours.C. Around eight hours.D. More than eight hours.15. A. They may not be able to concentrate well.B. They may get the feeling of being drunk.C. They may suffer from high blood pressure.D. They may lose weight easily in a short period of time.16. A. Military people are used to being deprived of sleep.B. Training can make people sleep less and suffer less.C. People can bank sleep by sleeping more beforehand.D. Sleeping earlier than usual makes people sleep less.Questions 17 through 20 are based on the following passage.17. A. Double Eleven sales in 2021.B. Unreliable factors of online shopping.C. Key points of Taobao's success ı n sales.D. Advantages and disadvantages of online shopping.18. A. People who are good at doing business.B. People who work seven days a week.C. People who have very busy schedules.D. People who dislike telephone shopping.19. A. Consumers can save a lot of time.B. It provides round- the- clock service.C. People can buy things without leaving their homes or offices.D. The quality of the product is the same as what is described online.20. A. Inferior quality. B. Various retailers.C. Efficient sales return.D. Convenient delivery.II. Grammar and VocabularySection ADirections: After reading the passages below, fill in the blanks to make the passages coherent and grammatically correct. For the blanks with a given word, fill in each blank with the proper form of the given word; for the other blanks, use one word that best fits each blankAI Weather Forecasting Can't Replace Humans- YetAs Hurricane Lee was curving（呈曲线）northward to the west of Bermuda in mid- September of last year, forecasters were busily consulting weather models and data from hurricane- hunter aircraft to calculate （21）________ the dangerous storm was likely to make landfall （着陆）: New England or farther east, in Canada. The sooner the meteorologists（气象学家）could do so, the earlier they could warn those in the path of damaging wind gusts and fierce storm surges By six days ahead of landfall, it was clear that Lee （22）________（follow）the eastward path, and warnings were issued, accordingly. But （mother tool- an experimental AI model called GraphCast-（23）________（mate）that outcome accurately three whole days before the forecasters' traditional models.GraphCast's prediction is a window into AI's potential （24）________（improve）weather forecasts. But whether it is a forecaster of a true sea change in the field or will simply become one of many tools （25）________ human forecasters consult to determine which way the winds will blow is still up in the air.GraphCast, developed by Google DeepMind, is the latest of several AI weather models （26）________（release）in recent years. Google's Metnet, first introduced in2020, is already being used in products such as the company's “now cast” in its weather app. All are advertised as having an accuracy that is comparable with or higher than（27）________ on the best non-AI forecasting computer models and have caused a sensation in meteorology, with GraphCast （28）________（cause）the most significant stir so far.The DeepMind research team had put GraphCast through its paces by feeding it historical weather data to see if it could accurately “predict” what happened. The study showed the AI performed equal to or even better than the gold standard.Yet （29）________ GraphCast becomes probabilistic-- and even if the model's resolution improves and the AI becomes more accurate in its forecasts of rain and storm intensity - modeling remains just a single component of the weather- prediction pipeline, says Hendrik Tolman, senior adviser for advanced modeling systems at the NWS. However, every expert described GraphCast and other Al models as additional devices in their tool kit. If AI （30）________produce accurate forecasts quickly and cheaply, there's no reason not to begin using it together with existing methods.But will there be a world where AI models replace physics- based models— and people -- in the future? Forecasts suggest there's little chance.Section BDirections: Complete the following passage by using the words or phrases in the box. Each word or phrase can only be used once. Note that there is one word or phrase more than you need.Alzheimer's Drug Approved Despite Fierce DebateThe -U. S. Food and Drug Administration （FDA）recently approved the drug Aduhelm, produced by Americanbiotechnology company Biogen with Japan's Eisai Co., to treat patients with Alzheimer's（老年痴呆症）disease. The approval was based on study results showing that the drug seemed“（31）________ likely” to benefit Alzheimer's patients, the FDA said.The decision, which could （32）________ millions of Alzheimer's patients and their families, has sparked disagreements among medical researchers. While the drug was shown to be effective in slowing the mental decline in patients' suffering from the disease, it was not proven to be effective in （33）________ its effects, the Associated Press reported. citing a study. The rate of mental decline in patients that had been administered Aduhelm was slowedby 22 percent when compared to patients who had received a placebo（安慰剂）. But even given these results, on a test that is conducted to evaluate the cognitive and （34）________ abilities of a patient, patients who were administered Adubelm only showed an increase of 0.39 in their- scores. And it's unclear how such metrics （度量标准）translate into practical benefits, like greater（35）________ or the ability to recall important details.The FDA's review of the drug has become a flashpoint in （36）________ debates over standards used to evaluate therapies for hard- to- treat conditions. On one side, groups representing Alzheimer's patients and their families sayany new therapy - even one of small benefit -deserves approval. But many experts ward that（37）________ the drug could set a dangerous example by opening the door to treatments of questionable benefit.Alzheimer's is an irreversible, （38）________ brain disorder that slowly attacks areas of the brain that are essential to memory, reasoning, communication, and basic daily tasks. In the final stages of the disease, the patientswill lose the ability to（39）________Science doesn't fully understand what causes Alzheimer's, but there's broad agreement that the brain plaque（斑点）that is being （40）________ by Aduhelm is one of the contributing factors. Evidence suggests family history, education, and chronic conditions like heart disease may all play a role. “This is a sign of hope but not the final answer,” said Dr. Richard Hodes, director of the U. S. National Institute on Aging.III. Reading ComprehensionSection ADirections: For each blank in the following passage there are four words or phrases marked A, B, C and D. Fill in each blank with the word or phrase that best fits the context.Some people like to read the instructions from start to finish before they take action while others study the diagrams and then jump right in. This 41 for one approach over another when learning new information is not uncommon. Indeed, the notion that people learn in different ways is such a universal belief in American culture that there is a thriving industry dedicated to 42 learning styles and training teachers to meet the needs of different learners.Just because a notion is popular, 43 , doesn't make it true. A recent review of learning styles found evidence to clearly support the idea that outcomes are 44 when instructional techniques align with （匹配）individuals' learning styles. Most previous investigations on learning styles focused on classroom learning, and assessed whether instructional style 45 outcomes for different types of learners. But is the 46 really where most of the serious learning occurs? Some might argue that, in this era of flipped classrooms and online course materials, students 47 more of the information on their own. That might explain why instructional style in the classroom matters little. It also 48 the possibility that learning styles do matter. Perhaps a 49 betweenstudents' individual learning styles and their study strategies is the key to ideal outcomes.To explore this 50 , researchers asked students enrolled in an anatomy class （解剖课）to complete an online learning styles assessment, answer questions about their study strategies and report details about the 51 they used outside of class（e. g. flash cards, review of lecture notes, anatomy coloring books）.Scores suggested that most students used multiple learning styles, but that no particular style 52 better outcomes than another. The focus in this study, however, was not on whether a particular learning style was more53 . Despite knowing their own, self- reported learning preferences, nearly 70% of students 54 to employ study techniques that supported those preferences. Given the popular belief that learning styles matter, and the fact that many students 55 poor academic performance on the lack of a match between their learning style and teachers' instructional methods, one might expect students to rely on techniques that support their personal learning preferences when working on their own.41. A. preference B. tendency C. phenomenon D. practice42. A. identifying B. exposing C. revealing D. establishing43. A. therefore B. moreover C. however D. instead44. A. best B. acceptable C. disappointing D. undesirable45. A. impacted B challenged C. confirmed D. supported46. A. network B. classroom C. school D. lecture47. A. require B. collect C. master D. demand48. A. limits B eliminates C examines D. raises49. A. comparison B. link C. balance D. match50. A. issue B. possibility C. field D. proposal51. A. equipment B. techniques C. notebooks D. assistance52. A. originated in B. resulted from C. resulted in D. took over53. A. important B. advantageous C meaningful D popular54. A. failed B. managed C. struggled D. attempted55. A. count B. concentrate C. blame D. conductSection BDirections: Read the following four passages. Each passage is followed by several questions or unfinished statements. For each of them there are four choices marked A, B, C and D. Choose the one that fits best according to the information given in the passage you have just read.（A）I was sure that I was to be killed. I became terribly nervous. I fumbled （摸索）in my pockets to see if there were any cigarettes, which had escaped their search. I found one and because of my shaking hands, I could barely get it to my lips. But I had no matches; they had taken those. I looked through the bars at my jailer. He did not make eye contact with me. I called out to him, “Have you got a light?” He looked at me, shrugged and came over to light my cigarette. As he came close and lit the match, his eyes unconsciously locked with mine. At that moment, I smiled. I don't know why I did that. Perhaps it was nervousness, perhaps it was because, when you get very close, one to another, it is very hard not to smile. In any case, I smiled. In that instant, it was as though a spark jumped across thegap between our two hearts, our two human souls. I know he didn't want to, but my smile leaped through the bars and generated a smile on his lips, too. He lit my cigarette but stayed near, looking at me directly in the eyes and continuing to smile.I kept smiling at him, now aware of him as a person and not just a jailer. And his looking at me seemed to have a new dimension too.“Do you have kids?” he asked.“Yes, here, here.”I took out my wallet and nervously fumbled for the pictures of my family. He, too, took out the pictures of his family and began to talk about his plans and hopes for them. My eyes filled with tears. I said that I feared that I'd never see my family again, never have the chance to see them grow up. Tears came to his eyes, too. Suddenly, without another word, he unlocked my cell and silently led me out. Out of the jail, quietly and by back routes, out of the town. There, at the edge of town, he released me. And without another word, he turned back toward the town.My life was saved by a smile, yes, the smile- the unaffected, unplanned, natural connection between people. I really believe that if that part of you and that part of me could recognize each other, we wouldn't be enemies. We couldn't have hate or envy or fear.56. The underlined sentence indicates that the author and the jailer started to have a ________ conversation.A. less impersonalB. more intenseC. less formalD. more friendly57. Which is true based on the first paragraph?A. My hands were shaking because of fear.B. The jailer was going to shoot me.C. I smile8 because I had to beg for life.D. He smiled to me because he wanted to.58. Their eyes were filled with tears because they both ________.A. took out the pictures of their familiesB. missed their families far awayC. had plans and hopes for futureD. feared that they would die59. How does a smile succeed in saving the author's life?A. By asking for the jailer to light a cigarette.B. By planning for an exchange of family pictures.C. By establishing natural connection between people.D. By hiding the human feelings of hate, envy or fear.（B）CareersHome>> How To ApplyFAQs on preparing your ApplicationQ: Should I target my Application to a specific Job Opening（JO）?A: Yes. Naturally, a customized cover note will also help you focus on the key aspects of your Application that relateto the JO, but it is also in your interest to target the Application according to the responsibilities and competencies of the position.Q: What's the difference between duties and achievements?A: Duties describe the specific responsibilities of your job. They accurately reflect what you are doing or have done in each of your previous jobs. In other words, it is the “what you do” of your job. Achievements describe in specific terms “how well” you did in your job.Q: Many of my achievements are team- based, how do I draft them in my Application?A: You should include your team- based achievements in your Application. Indicate that you were part of a team, and describe your specific role in reaching the goal.FAQs on general Application guidelinesQ: Can I save my Application?A: Yes. You should save your Application when you make changes and/ or update it. It is recommended that you save different versions of your Application in Word format and then edit the Application online according to the post for which you are applying.Q: Can I update my Application to apply for a new JO?A: Yes. Each time you apply for a new JO, we recommend that you review your Application and update it , if appropriate, or target it to better reflect your suitability for the new JO. Your updates will not affect the content of Applications previously submitted against other JOs.Q: Must I use up all the available characters in each section of my Application?A: No. In fact, doing so may result in an unnecessary lengthy Application. Unless you have an enormous range of experiences, there is no reason to use up all the space given. Applicants are encouraged to list their duties and achievements in a clear and brief manner.60. Which of the following descriptions best shows your achievements?A. I've developed various interests, ranging from oil painting to designing model.B. I'm good at creating proposals for new product ideas aimed at a specific market.C. I'm in charge of the clearance, production and distribution of information material.D. I succeeded in directing a video presentation, assisting our group to win the first prize.61. If you want to apply for another JO, you'd better __________.A. target your focus on your interest in the JOB. save your latest application in Word formatC. Serape one application with all your competenciesD. update your application to match new requirements62. Applicants are expected to __________ in their applications.A. introduce what JOs they have previously applied toB. list the greatest achievements they have made in detailC. give key information about their experiences and achievementsD provide the results of their tests, assessments and examinations（C）Atlantis is the legendary island that sank beneath the waves in the distant past, taking down with it an advanced civilization. Is it possible that we will ever find it? Or, more importantly did it even exist?The short answer to both: No. All available evidence indicates that the philosopher Plato, sometime around 360 B.C., invented the island nation to illustrate a point about the dangers of aggressive imperialism（势力扩张）. In Plato's telling, Atlantis was no utopia. Rather, it was a centrist to an idealized version of Athens from long before Plato's time. This ancient Athens was very similar to Plato's notion of the ideal state. Plato laid out the details for what such a state would look like in his famous work, I he Republic. It should be small and virtuous. The residents of Atlantis, on the other hand, were eventually “filled with an unjust lust for possessions and power," according to Plato's character who described the island.In Plato's texts, Atlantis was “larger than Libya and Asia combined,”（which, in Plato's time. would have referred to modern- day northern Africa and over half of Turkey）. It was situated in the Atlantic Ocean, somewhere outward from the Strait of Gibraltar. It's a landmass large enough that, if it really existed somewhere underwater in the Atlantic, it would certainly appear on sonar maps of the ocean floor.So how did Atlantis come to represent a lost utopic civilization? For that, you can mostly blame （or thank）Ignatius Donnelly. In 1882, the former U. S. Congressman published Atlantis. The Antediluvian World. The book laid out 13 hypotheses, centered on the idea that Atlantis had truly existed, and indeed represented a place “where early mankind dwelt for ages in peace and happiness. According to Donnelly, Atlantis was the original source of many ancient civilizations around the world. If one followed the clues in Plato's writing, Donnelly believed, Atlantis could be found. He was inspired by a remarkable discovery in the early 1870s. An amateur archaeologist claimed to have unearthed the legendary city of Troy based on Homer's The Iliad. If Troy, long thought to be fictional, was real, why shouldn't Atlantis be, too?Donnelly was certain of his theory, predicting that hard evidence of the sunken city would soon be found, and that museums around the world would one day be filled with artifacts from Atlantis. Yet about 140 years have passed without a trace of evidence. The Atlantis legend has been kept alive, fueled by the public's imagination and fascination with the idea of a hidden. long- lost utopia. Yet the “lost city of Atlantis was never lost; it is where it always was: in Plato's books.63. What can we learn about Plato?A. He predicted that Atlantis would be' destroyed by aggressive imperialism.B. He was inspired by utopia to gradually form the notion of the ideal state.C. He created the setting in which residents of Atlantis were not virtuous.D. He witnessed Atlanteans' pursuit of an unjust lust for possessions and power.64. Homer's The Iliad is mentioned ___________.A. to demonstrate the actual existence of the legendary city of Troy.B. as indirect evidence of the credibility of Plato's account of Atlantis.C. because it is a great piece of fictional writing about an ancient legend.D. because it contains many clues about the legendary city of Troy.65. According to the passage, Atlantis was ___________.A. a long- lost small utopia with many virtuous residents.B. a large landmass situated in the Atlantic Ocean.C. the original source of many ancient civilizations.D. Plato's invention against which to highlight his ideal.66. Which of the following is the best title for this passage?A. Plato, Atlantis and How the City Collapsed and Finally Got LostB Plato Told a Lie, and Ignatius Donnelly was to Blame for ItC. The History, Legends, and Evidence of the Lost City of AtlantisD. Where Is the Lost City of Atlantis — and Does It Even Exist?Section CDirections: Read the passage carefully. Fill in each blank with a proper sentence given in the box. Each sentence can be used only once. Note that there are two more sentences than you need.Bringing Light to the Darkness with Crisco ArtMost paintings are best enjoyed in galleries with good lighting. But an Italian artist who goes by the name Crisco is changing the way we look at paintings with a new approach: glow （发光）- in- the- dark paint.Crisco's paintings are beautiful in normal lighting, but it is when the lights go down that they really come alive. （67）_________ His art mostly shows landscapes. Trees, horizons, and especially starry skies come alive with the glow of his paints. At the center of most of his work, there is often a human or animal figure. The figure may be just a shadow surrounded by the glowing colors, but it often appears to be the source of the light. （68）_________ Instead, they are all bright pictures of hope, life, wonder, and growth. They are Crisco's way o t adding a little light to the world.Crisco's full name is Cristoforo Scorpiniti.（69）_________ Instead of letting a negative experience get the best of him, he threw himself into a new pursuit: art. According to Crisco, he paints with glowing colors to inspire hope. Though his paintings often show night scenes that look good in the dark, Crisco does not focus on the darkness. Instead, he uses his paintings to express positivity by creating light in the darkness.A lot of his best work has come out of just painting what he felt at the time without any plan or structure.（70）_________ With over half a million followers on Instagram, Crisco is already popular on social media for his unique paintings. He'll surely only get more famous in the future for his inspiring paintings that beautifully mix darkness and light.IV. Summary Writing71. Directions: Read the following passage. Summarize the main idea and the main point（s）of the passage in no more than 60 words. Use your own words as far as possible.Are EV Really Environmentally Friendly?Many consumers are opting for an electric vehicle （EV）or plug- in hybrid electric vehicle （PHEV）to replace their polluting gas- powered cars. These electrified vehicles are rising to popularity on the premise of environmental conservation and eliminating the need for harmful emissions. There are a couple of things. however, to consider before concluding that EVs are the most environmentally friendly option for consumers.Where do electric cars get their energy? Although EVs create no emissions on board, they typically draw power from lithium- ion batteries. These batteries require charging, either at home or via a publicly accessible charging station. Since EV charging infrastructure is mainly reliant on the power grid - specifically, the grid draws power from plants like coal plants - although your EV does not produce any harmful emissions as you drive it, burning fossil fuels is involved in fueling it. Moreover, temperature extremes like excessive coldness or heat can dramatically reduce lithium- ion battery life. Carnegie Mellon University's Department of Engineering and Technology says that the most extreme cases of coldness will compromise efficiency by as much as 40%. The decreased efficiency is an issue if the power stored in the battery packs of EVs is sourced from fossil fuel- burning.Besides the power source, metal s such as lithium and cobalt are wrapped up in environmentally and socially questionable processes, too. One of the first environmental issues lithium batteries pose is how to dispose of them properly. In an average battery recycling plant, all parts of the battery are shredded into a powder using a mechanical shredder and then either melted or dissolved into acid —recycling lithium batteries isn't as simple. Lithium batteries are typically made up of a mix of different elements including cobalt, nickel, manganese and iron —cobalt especially known to be a hazardous substance. In addition, most studies associate lithium mining in South America from salt brine with salinization（盐化）of freshwater that the locals need to survive. Since the mineral contains dangerous substances, the mining process also contaminates the local water basins. So, lithium extraction exposes the local ecosystems to poisoning and other related health problems.V. TranslationDirections: Translate the following sentences into English, using the words given in the brackets.72.他那种急于求成的心态让他无缘冠军宝座。

做事的过程减少多余的形式英语作文

做事的过程减少多余的形式英语作文Streamlining Processes: Minimizing Redundancies and Maximizing Efficiency.In the realm of organizational optimization, thepursuit of efficiency and productivity reigns supreme. One pivotal aspect of enhancing these qualities lies in streamlining processes—meticulously examining existing workflows to identify and eliminate redundant or superfluous steps. By doing so, organizations can unlock significant benefits, ranging from reduced costs and improved resource allocation to enhanced customer satisfaction and a more streamlined employee experience.Redundancies in processes manifest themselves in various forms. One common type is duplication, where the same task or function is performed multiple times by different individuals or departments. This can lead to inconsistencies, errors, and a waste of valuable resources. Another form of redundancy is unnecessary complexity, whereprocesses are unnecessarily intricate or convoluted, making them difficult to understand and execute. This can resultin delays, bottlenecks, and employee frustration.To effectively streamline processes and minimize redundancies, a comprehensive and systematic approach is essential. The following steps provide a roadmap for organizations to embark on this optimization journey:1. Process Mapping: The initial step involves meticulously documenting all existing processes, outlining each step, activity, and stakeholder involved. This visual representation provides a comprehensive overview of the workflow and helps identify potential areas for improvement.2. Identification of Redundancies: With the process map in place, organizations can systematically analyze eachstep to identify redundancies. This involves examining whether the same task is being repeated, whether there are unnecessary delays or bottlenecks, and whether any stepscan be eliminated or consolidated.3. Root Cause Analysis: Once redundancies are identified, it is crucial to delve deeper into their underlying causes. This can involve conducting interviews with stakeholders, reviewing documentation, and analyzing data to understand why redundancies exist in the first place.4. Redesign and Simplification: Armed with an understanding of the root causes, organizations can embark on redesigning and simplifying processes to eliminate redundancies. This may involve automating certain tasks, eliminating unnecessary approvals or signatures, or consolidating multiple steps into a single streamlined workflow.5. Implementation and Monitoring: The redesigned processes must then be implemented and closely monitored to ensure their effectiveness. This involves setting up metrics to track performance improvements, identifying any remaining bottlenecks, and making necessary adjustments along the way.6. Continuous Improvement: Streamlining processes is an ongoing journey, not a one-time event. Organizations must establish a culture of continuous improvement, regularly reviewing their processes and seeking opportunities for further optimization.By embracing these steps and fostering a mindset of continuous improvement, organizations can reap the numerous benefits of streamlined processes. Reduced costs, improved resource allocation, enhanced customer satisfaction, and a more efficient and engaged workforce are just a few of the rewards that await those who embark on this transformative journey.Conclusion.In an era characterized by rapid technological advancements and intensifying competition, the ability to operate with efficiency and minimize redundancies is paramount for organizations that seek to thrive. Streamlining processes is a powerful tool that can empower organizations to unlock their full potential, maximizingtheir resources, enhancing their operations, and ultimately achieving their strategic objectives. By systematically identifying and eliminating redundancies, organizations can create a leaner, more agile, and more responsive enterprise that is well-positioned to navigate the challenges and capitalize on the opportunities of the future.。

科技英语翻译1

驱动这些机器的动力装置是一台50马力的感应电动机。
► 2）通顺易懂 ► 译文的语言符合译语语法结构及表达习惯，容易为读者所理解和接受。
► A. When a person sees, smells, hears or touches something, then he is perceiving.
2. Cramped(狭窄的) conditions means that passengers’ legs cannot move around freely.
空间狭窄，旅客的两腿就不能自由活动。
3. All bodies are known to possess weight and occupy space.
忠实、通顺（普遍观点）
► 科技英语文章特点：(well-knit structure;tight logic;various styles)结构严谨，逻辑严密，文体多样
1. 科技翻译的标准：准确规范，通顺易懂，简洁明晰 1）准确规范
所谓准确，就是忠实地，不折不扣地传达原文的全部信息内容。所谓规范，就是译文要符合所涉及的科学技或某个专业领域的专业语言表
实验结果等，而不是介绍这是这些结果，理论或现象是由谁发明或发现的。
► In this section, a process description and a simplified process flowsheet are given for each DR process to illustrate the types of equipment used and to describe the flow of materials through the plant. The discussion does not mention all the variations of the flowsheet which may exist or the current status of particular plants. In the majority of the DR processes described in this section, natural gas is reformed in a catalyst bed with steam or gaseous reduction products from the reduction reactor. Partial oxidation processes which gasify liquid hydrocarbons, heavy residuals and coal are also discussed. The reformer and partial oxidation gasifier are interchangeable for several of the DR processes.

petronas substance misuse policy

petronas substance misuse policy题目：Petronas Substance Misuse Policy: Promoting a Safe and Healthy WorkplaceIntroduction:Petronas, as one of the world's leading oil and gas companies, recognizes the importance of maintaining a safe and healthy workplace. The company's Substance Misuse Policy is designed to safeguard its employees' well-being and create a productive working environment. This article will provide a comprehensive overview of the policy, discussing its objectives, key provisions, implementation strategies, and the positive impact it has on employees and the organization.Body:1. Objectives of Petronas Substance Misuse Policy (250 words)The primary objectives of the Petronas Substance Misuse Policy are:a. Ensuring the safety and well-being of employees by preventing and addressing substance misuse in the workplace.b. Promoting a healthy work environment that supports employee well-being and productivity.c. Complying with legal requirements and ethical standards related to substance misuse.d. Providing support and assistance to employees struggling with substance misuse issues.e. Reducing the potential risks and liabilities associated with substance misuse within the organization.2. Key Provisions of Petronas Substance Misuse Policy (500 words)The policy includes several essential provisions aimed at achieving its objectives:a. Prohibition of Substance Misuse: Petronas strictly prohibits the unauthorized use or possession of illicit drugs, alcohol, and other controlled substances during working hours, on company premises, or while performing job duties.b. Drug and Alcohol Testing: The policy mandates drug and alcohol testing for employees in safety-sensitive positions, as well as for those suspected of substance misuse. Random testing may also be conducted to deter substance misuse.c. Employee Education and Awareness: Petronas is committed to raising awareness about substance misuse through regular employee training programs and informational campaigns. Employees are educated on the potential risks, consequences, and available resources for substance misuse.d. Confidentiality and Non-Discrimination: The policy ensures that employee information related to substance misuse is treated confidentially and that individuals seeking assistance are protected from discrimination or retaliation.e. Support and Rehabilitation: Petronas provides confidential support and assistance to employees struggling with substance misuse. Rehabilitation programs, counseling services, and employee assistance programs are available to encourage recovery and provide guidance.f. Disciplinary Actions: Violations of the Substance Misuse Policy may result in disciplinary actions, including warnings, suspensions, and termination, depending on the severity of the infraction.3. Implementation Strategies (500 words)To effectively implement the Substance Misuse Policy, Petronas employs several strategies:a. Policy Communication: The policy is communicated to all employees through various channels, including orientation programs, employee handbooks, intranet resources, and regular reminders.b. Training and Education: Training sessions are conducted to ensure employees understand the policy's provisions, their responsibilities, and the potential consequences of substance misuse. These programs also offer guidance on identifying signs of substance misuse in colleagues and providing appropriate support.c. Testing Procedures: Petronas establishes clear guidelines and protocols for drug and alcohol testing, ensuring transparency, fairness, and accuracy in the testing process. These procedures may be conducted by trained professionals or authorized third-party agencies.d. Employee Assistance Programs: The company offersconfidential counseling services and employee assistance programs to support individuals struggling with substance misuse. These programs aim to provide guidance, promote awareness, and help employees achieve recovery and healthier lifestyles.e. Monitoring and Evaluation: Periodic evaluation is conducted to assess the effectiveness of the Substance Misuse Policy. Feedback from employees and relevant stakeholders is taken into consideration, and necessary amendments are made to ensure continual improvement.f. Collaboration with External Partners: Petronas collaborates with external organizations, such as healthcare providers and community support groups, to enhance the effectiveness of its substance misuse prevention efforts. This collaboration ensures comprehensive support and access to additional resources for employees in need.4. Impact on Employees and the Organization (250 words)The implementation of the Substance Misuse Policy has had significant benefits for both employees and the organization:a. Employee Well-being: The policy promotes a safe and healthy working environment, safeguarding employees' physical and mental well-being. It provides support for individuals struggling with substance misuse, facilitating their recovery and overall wellness.b. Increased Productivity: By reducing substance misuse-related incidents, the policy enhances employees' focus, concentration, and overall productivity. It helps maintain a workforce that is more engaged and driven towards achieving organizational goals.c. Risk Mitigation: The policy minimizes the potential risks and liabilities associated with substance misuse, such as accidents, injuries, legal repercussions, reputational damage, and increased insurance costs. This proactive approach protects the organization's financial stability and reputation.d. Compliance and Ethical Standards: The policy ensures compliance with legal requirements related to substance misuse while promoting ethical standards within the organization. This strengthens Petronas' reputation as a responsible corporate citizen.e. Positive Organizational Culture: The Substance Misuse Policy fosters a culture of safety, well-being, and accountability within the organization. It sends a clear message that substance misuse is unacceptable and supports a workplace where employees can thrive.Conclusion (100 words)Petronas' Substance Misuse Policy serves as a vital framework for maintaining a safe, healthy, and productive workplace. By establishing clear guidelines, providing support resources, and emphasizing prohibition and prevention, Petronas demonstrates its commitment to employee well-being and organizational excellence.。

Crouse-Hinds PRE-formance

PRE-formance ™Giving you the convenience of a pre-fabricated product, plus the flexibility to accommodate job site requirements.Contractors are continually looking for ways to improve job siteefficiency and properly align skilled resources to meet tight commercial construction project deadlines. PRE-formance ™ delivers the pre-engineered and pre-assembled combination of mounting method, outletbox, plaster ring, devices and leads to simplify branch wiring installation.BASIC ASSEMBLIES• Available with the most popular drawn and welded boxes with ground screw and pigtail lead already installed• Patented Uni-Mount ™ cover combines plaster ring and mounting method• Standard pre-fabricated assemblies with mounting brackets, boxes, mud rings, ground screw and pigtail leads• Most popular configurations available from stockCUSTOM ASSEMBLIES• Cafeteria style selection of our extensive line of mounting brackets, boxes, plaster rings, wiring devices and other associated branch wiring accessories• Assembled-to-order pre-fabricated products for both AC/MC and EMT applications• Can be ordered with: wiring devices with pigtail leads and push-inconnectors, AC/MC or EMT connectors installed, cable whips attached per customer application• Assembled from stock components to meet tight job requirementsCOMPLETE ASSEMBLIES• The most complete turn-key solution for commercial construction projects; the process begins with your architectural and electricalengineering drawings and delivers a total pre-fabricated branch wiring system: custom produced, labeled, packaged by room and floor and delivered to your exact location• The ideal solution for commercial buildings with repetitive installations, such as hotels, condominiums, commercial and retail offices, hospitals and apartments• Job-specific customized drawings and labels simplify material handling and speed installation• Dedicated project management and engineering expertise through every step of the project• Innovative PRE-formance products are designed by contractors forcontractors, and provide ease of wiring and job site flexibility to get the job done right and on time• Includes flexible products designed with pre-fabrication, productivity, safety and job site speed in mind• Contractors can realize 30 to 40% labor savings over traditional “stick-build” wiring methods for greatly improved job site efficiencyCertifications and compliances:• UL Listed and cUL Listed •UL File No. E-23156PRE-formance ™Basic assembliesBOXES WITH PRE-INSTALLED GROUND SCREW & PIGTAILBoxes with pre-installed ground screw and pigtail provide a simple, readily available way to meet grounding and bonding requirements for metal boxes. Includes the 4” or 411/16” square box with ground screw and lead installed A .Certifications and compliances:• UL Listed and cUL Listed •UL File No. E-23156Cat. #Description Pre-fabricated box, cover, ground screw & lead assembly Ca pa city cu. in.Unit qty.Wt. lbs. per 100For conduit TP403PF 4D 1/” and 3/” KO welded box with ground screw and lead30.32584A Standard ground pigtail is #8 - 32 ground screw with 8” insulated No. 12 copper wire.Basic assembliesUNI-MOUNT ™ASSEMBLIESUni-Mount assemblies combine the patented Uni-Mount cover(mounting method and mud ring, all in one) to a 4” square box with ground screw and lead installed to simplify ordering, receiving and improve job site speed.Pre-fabricated box features:• Uni-Mount provides a secure box support and features a built-in plaster ring• Can be field assembled with outlet box for power applications or used without a box for low voltage applications• Pre-fabricated Uni-Mount is available with most popular outlet boxes with a choice of 1/2”, 5/8” or 3/4” raised cover and includes ground screw and lead• Rigid bracket design eliminates the need for far side support • Guide tabs ensure alignment on studsUni-Mount features:• Uni-Mount combines the features of a mounting device plate with those of a box support, giving you one universal plate for all of your needs; specifically designed for use with metal or woodstudsTP404TP403TP414TP434TP43611/2” deep – welded 22.0” cubic capacity 21/8” deep – welded 30.3” cubic capacity 11/2” deep – drawn 21.0” cubic capacity 21/8” deep – welded 30.3” cubic capacity 21/8” deep – welded 30.3” cubic capacityCertifications and compliances:• UL Listed and cUL Listed •UL File No. E-23156• New and improved Uni-Mount incorporates four small holes on the left side (support side) of the bracket; these holes allow for the attachment of box mounting brackets to allow for use of both sides of the stud • The holes are strategically located to accept the B-Line BB423 bracket; additionally, the viewing hole has been significantly enlarged (and is now diamond shaped) to make it even easier to find mark lines on the studCat. #Description Pre-fabricated box, cover, ground screw & lead assemblyCa pa city cu. in.Unit qty.Wt. lbs. per 100For conduit TP30-4S 11/” deep welded box, 1/” raised single gang Uni-Mount cover, ground screw and lead 25.825115TP37-4342/8” deep drawn box, /4” raised two gang Uni-Mount cover, ground screw and lead39.325138PRE-formance ™Basic assembliesAdditional Uni-Mount/box configurations available. Consult factory for details.Remove the ‘PF’ in catalog number for boxes without ground screw and lead. For stranded wire, replace ‘PF’ with ‘PFA’.Cat. #Description Pre-fabricated box, cover, ground screw & lead assembly Ca pa city cu. in.Unit qty.Wt. lbs. per 100For armored & metal-clad (MCI) cable - clamps in each end TP30-45411/” deep welded box assembled to 1/” raised single gang Uni-Mount cover 24.825114UNI-MOUNT ™ASSEMBLIES (CONTINUED)Uni-Mount assemblies combine the patented Uni-Mount cover(mounting method and mud ring, all in one) to a 4” square box with ground screw and lead installed to simplify ordering, receiving and improve job site speed.Cat. #Description Pre-fabricated box, cover, ground screw & lead assemblyCa pa city cu. in.Unit qty.Wt. lbs. per 100For non-metallic cable – clamps in each end 11/” deep welded box assembled to 1/” raised single gang Uni-Mount cover 24.825114Single sided, double sided, floor mount, telescoping slider,multi-mount, open bracket & T-bar assembliesUL and cUL Listed UL File No. E-324733SINGLE SIDED ASSEMBLIESSingle sided direct mount assemblies – all catalog numbers contain a single sided direct mount bracket (for 21/2” and 31/2” studs), 4” square steel box, mud ring and 8” insulated solid ground wire with ground screw.4” and 6” far side supports are available. Replace ‘PFH3’ (for 2/” and 3/” studs) with ‘PFH4’ (4”) (BB44) or ‘PFH6’ (6”) (BB46). Refer to the PRE-formance catalog numbering system at the end of this section for additional assembly options and configurations.FLOOR MOUNT ASSEMBLIESFloor mount assemblies – all catalog numbers contain an 18” floor mount bracket, 4” square steel box, mud ring and 8” insulated solid ground wire with ground screw.Refer to the PRE-formance catalog numbering system at the end of this section for additional assembly options and configurations.DOUBLE SIDED ASSEMBLIESDouble sided direct mount assemblies – all catalog numbers contain a double sided direct mount bracket (for 21/2” and 31/2” studs), 4” square steel box, mud ring and 8” insulated solid ground wire with ground screw.4” and 6” far side supports are available. Replace ‘PF3DS’ (for 2/” and 3/” studs) with ‘PF4DS’ (4”) (BB74) or ‘PF6DS’ (6”) (BB76). Refer to the PRE-formance catalog numbering system at the end of this section for additional assembly options and configurations.Cat. #Description Pre-fabricated box, cover, ground screw & lead assemblyPFH3-4D58BB423 single sided bracket, TP403 21/” deep box with pigtail, 5/” raised 1G mud ring PFH3-4S275BB423 single sided bracket, TP404 1/2” deep box with pigtail, /4” raised 2G mud ringUL and cUL Listed UL File No. E-324733Cat. #Description Pre-fabricated box, cover, ground screw & lead assemblyPF3DS-4D58BB73 double sided bracket, TP403 21/” deep box with pigtail, 5/” raised 1G mud ring PF3DS-4S275BB73 double sided bracket, TP404 1/2” deep box with pigtail, /4” raised 2G mud ringUL and cUL Listed UL File No. E-324733Cat. #Description Pre-fabricated box, cover, ground screw & lead assemblyPF18FM-4D58BBF18 floor mount bracket, TP403 21/” deep box with pigtail, 5/” raised 1G mud ring PF18FM-4S275BBF18 floor mount bracket, TP404 1/2” deep box with pigtail, /4” raised 2G mud ringPRE-formance ™Single Sided, double sided, floor mount, telescoping slider, multi-mount, open bracket & T-bar assembliesTELESCOPING SLIDER ASSEMBLIESTelescoping slider assemblies – all catalog numbers contain an11-18” telescoping slider bracket, 4” square steel box, mud ring and 8” insulated solid ground wire with ground screw.MULTI-MOUNT ASSEMBLIESMulti-mount assemblies – all catalog numbers contain a 16” stud spanning multiple mount bracket. Each position may contain a 4” square steel box, mud ring and 8” insulated solid ground wire with ground screw.Refer to the PRE-formance catalog numbering system at the end of this section for additional assembly options and configurations.15” - 26” Telescoping slider assemblies are available. Replace ‘PF16TS’ (BB216TS) with ‘PF24TS’ (BB224TS).Refer to the PRE-formance catalog numbering system at the end of this section for additional assembly options and configurations.UL and cUL Listed UL File No. E-324733Cat. #Description Pre-fabricated box, cover, ground screw & lead assemblyPF16TS-4D58BB216TS telescoping slider bracket, TP403 21/” deep box with pigtail, 5/” raised 1G mud ringUL and cUL Listed UL File No. E-324733Cat. #Description Pre-fabricated box, cover, ground screw & lead assemblyPF3MM-4D58 BB816 multiple box bracket, 1st position TP403 21/” deep box with pigtail, 5/” raised 1G mud ring, 2nd and 3rd positions openOPEN BRACKET ASSEMBLIESOpen bracket assemblies – all catalog numbers contain a 16” stud spanning open bracket. Each position may contain a 4” square steel box, mud ring and 8” insulated solid ground wire with ground screw.Refer to the PRE-formance catalog numbering system at the end of this section for additional assembly options and configurations.T-BAR ASSEMBLIEST-bar ssemblies – all catalog numbers contain a BA50 T-bar fastener and a 4” square or octagon box.Single sided, double sided, floor mount, telescoping slider, multi-mount, open bracket & T-bar assembliesUL and cUL Listed UL File No. E-324733Cat. #Description Pre-fabricated box, cover, ground screw & lead assemblyPF16BO-4D58 BB716 open bracket, 1st position TP403 21/” deep box with pigtail, 5/” raised 1G mud ring, 2nd and 3rd positions openUL and cUL Listed UL File No. E-324733Cat. #Description Pre-fabricated box, cover, ground screw & lead assemblyPFBH24-4SN BA50 bar hanger, TP404 11/” deep box。

FeasiblilityofPr...

concrete panels. The panels will all be pretensioned in the trans-verse direction during fabrication and post-tensioned together in the longitudinal direction after place-ment. The advantage of using pre-stressed panels is a significant in-crease in the durability of the pavement, with a significant re-duction in required pavement thickness. For example, an 8 in. thick precast, prestressed pave-ment can be designed for the same design life as a 14 in. thick contin-uously reinforced concrete pave-ment by simply adjusting the pre-stress level in the pavement. This adjustment will not only result in significant material cost savings but will also allow for more flexi-bility when pavements are con-structed in areas with overhead clearance restrictions, such as un-der bridges.The proposed concept consists of three different types of panels, as shown in Figure 1. The base panels (Figure 1a) are the “filler”panels between the joint panels and central stressing panel(s). The central stressing panel (Figure 1b) is a panel similar to the base pan-el, with the addition of pockets cast into the panel. These pockets will allow the post-tensioning strands to be stressed at the center of the slab, rather than at the an-chorage, which will be cast into the joint panels. The joint panels (Figure 1c) will contain an expan-sion joint detail (Figure 2), similar to that of bridge expansion joints, which will absorb the significant expansion and contraction move-ments of the pavement with daily and seasonal temperature cycles.A typical panel assembly is shown in Figure 3. The slab length (between expansion joints) will be varied by an increase in the num-ber of base panels between the joint panels and central stressing panels. After all of the panels are set in place, the post-tensioning strands will be inserted into the ducts via the central stressing pockets and threaded through all of the panels to self-locking,spring-loaded post-tensioning an-chors cast into the joint panels.The use of self-locking anchorswill allow the strands to simply bepushed into the anchors fromsome point along the pavement,most likely from small pocketscast into the joint panels.After the post-tensioningstrands are tensioned from thecentral stressing pockets, thepockets will be filled with a fast-setting concrete, which will havesufficient strength by the timetraffic is allowed back onto thepavement. The strands will thenbe grouted in the ducts via inlets/vents located at the expansionjoints and at the stressing pockets.The intermediate joints betweenthe individual panels will then besealed with a low-viscosity, liquidsealant. If needed, the pavementcan then be diamond-ground tosmooth out any major irregulari-ties, and any major voids beneaththe pavement can be filled bystandard grout injection or expan-sive polyurethane foam.To obtain a smooth riding sur-face over the assembled pave-ment, continuous shear keys willbe cast into the panel edges, asshown in Figure 1, to ensure exactvertical alignment of the panels asthey are set in place. Additionally,the panels will be placed over athin, 1 to 2 in. thick, asphalt level-ing course, which should providea smooth, flat surface on whichthe panels can be placed to mini-mize the amount of voids beneaththe panels. A single layer of poly-ethylene sheeting will also beplaced over the asphalt levelingcourse to reduce the friction be-tween the leveling course and theprecast panels.Through the feasibility studydescribed above, the researchersdeveloped a feasible concept for aprecast concrete pavement. Thisconcept should meet the require-ments for both expedited con-struction and increased durability,which will result in both tremen-dous savings in user costs and anincreased design life.With respect to expedited con-struction, the proposed concepthas many features that will allowfor construction to take place dur-ing overnight or weekend opera-tions. First, the asphalt levelingcourse can be placed well in ad-vance of the precast panels. Thiswill allow for the entire asphaltleveling course to be placed at onetime, rather than just prior to theplacement of the precast slabs.Traffic on the leveling courseshould not have a detrimental ef-fect as long as the panels areplaced within a reasonable amountof time after the leveling course.Second, neither the stressingpockets nor the post-tensioningducts must be filled or groutedprior to exposure to traffic. Thepockets can simply be temporarilycovered and the strands can begrouted during a subsequent con-struction operation. Finally, tem-Figure 2. Expansion joint detail to be cast into the joint panels.6"2"1/4" Ø Stainlessporary precast ramps can simply be placed at the end of the slab to provide a transition for traffic onto and off the new pavement. These ramps can then be reused during subsequent operations.User delay costs can be sub-stantially reduced by limiting con-struction to an overnight or week-end timeframe. As an example, the computer program QUEWZ was used to compute and compare user delay costs for precast pave-ment construction and for conven-tional pavement construction. For conventional pavement construc-tion, wherein traffic is diverted through the construction zone for 24 hours per day until construc-tion is complete, the user delay costs were computed as approxi-mately $383,000 per day. On the other hand, precast pavement con-struction, wherein traffic is only diverted from 8 p.m. to 6 a.m. dai-ly, results in user delay costs of only $1,800 per day. Although it may not be possible to place as much precast pavement as con-ventional pavement during one day, the savings in user costs far outweigh any additional construc-tion time.In addition to expedited con-struction, precast pavement also offers enhanced durability. First, the panels will be cast in a con-trolled environment at a precast yard. This will allow for flexibili-ty with the concrete mix, making the use of lightweight, high per-formance, and other concretes possible. Second, because pre-stressing will be incorporated, cracking in the pavement can be prevented. This will reduce, if not eliminate, spalls and punchouts during the design life of the pave-ment. Prevention of cracking will also protect the post-tensioning strands in the pavement. The cast-in-place prestressed pavement constructed in 1985 on Interstate35 in McLennan County, Texas, isa testament to the increased dura-bility of prestressed pavements. Finally, because the precast pan-els will generally be thinner than conventional pavements, and be-cause there will be a great deal of control over the temperature gra-dient in the precast panels during casting, “built-in curl” will be sig-nificantly reduced, if not eliminat-ed. This will greatly reduce tem-perature curling stresses in the pavement.The Researchers Recommend...The proposed concept appears to be a feasible method for expe-diting construction of portland cement concrete (PCC) pave-ments. However, the true feasibil-ity of this concept will be realized only through actual implementa-tion. Therefore, a staged imple-mentation strategy is recommend-ed for testing these concepts and slowly introducing this new con-struction technique into current practices.Staged implementation will begin with small pilot projects aimed at refining the proposed concepts and streamlining the construction process. The pilot projects should be constructed on pavements that can be closed dur-Figure 3. Typical panel assembly.ing construction with a very mini-mal impact on traffic, such as cer-tain frontage roads or rest area roads. Any necessary laboratory testing should be completed prior to the construction of the pilot projects to ensure the viability of certain aspects, such as the spring-loaded anchors and strand place-ment procedures.The pilot projects will be fol-lowed by rural implementation, wherein the construction process will be further streamlined under simulated time constraints. As with the pilot projects, rural imple-mentation should be undertaken on pavements that will not have a very significant impact on traffic if problems occur during construc-tion. Rural implementation should take place, however, on a road that will experience significant traffic loading, such as a rural interstate.Finally, after rural implementa-tion, urban implementation will present the most challenges to pre-cast pavement construction. Urban implementation should take place on an urban intersection or major arterial where road closure must be limited to overnight or weekend operations. By the time urban im-plementation is undertaken, how-ever, the construction process should be fully streamlined to ac-commodate strict time constraints.Implementation will ultimately determine the feasibility of the precast concrete pavement con-cepts presented in this report. In the end, a simple concept that is easily adaptable to existing tech-niques yet not restricted by current practices will ensure the viability of precast concrete pavements.DisclaimerFor More Details …Research Supervisor: B. Frank McCullough, Ph.D., P.E., phone: (512) 232-3141,email:************************.eduTxDOT Project Director:Gary Graham, P.E., phone: (512) 467-5926,email:*****************The research is documented in the following report:Report 1517-1, The Feasibility of Using Precast Concrete Panels to Expedite HighwayPavement Construction, Draft January 2001To obtain copies of the report, contact: CTR Library, Center for Transportation Research,phone:(512)232-3138,email:*************.This research was performed in cooperation with the Texas Department of Transportation and the U. S. Department of Transportation, Federal Highway Administration. The contents of this report reflect the views of the authors, who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official view or policies of the FHWA or TXDOT.This report does not constitute a standard, specification, or regulation, nor is it intended forconstruction, bidding, or permit purposes. Trade names were used solely for information and not for product endorsement. The engineer in charge was Dr. B. Frank McCullough, P.E. (Texas No. 19914).。

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Precluding Useless Events for On-Line Global Predicate DetectionsLi-Hsing YenDepartment of Computer Science and Information EngineeringChung Hua UniversityHsinchu,Taiwan30067,R.O.C.lhyen@.twAbstractDetecting global predicates is an important task in test-ing and debugging distributed programs.In this paper, we propose an approach that effectively precludes useless events for global predicate detection,facilitating the pro-cess of an independent on-line checking routine.To identify more useless events than a simple causality-check method can do,our method tracks and maintains the precedence information of event intervals as a graph.To reduce the potentially expensive space and time cost as the graph ex-pands,we propose an effective scheme to prune the graph. The performance of our method is analyzed and evaluated by simulations.The result shows that our approach outper-forms conventional approaches in terms of the number of useless events found.1.IntroductionOne important task in testing and debugging a distributed program is to answer whether a given execution run of this program fulﬁlls a particular property.Such a property is of-ten speciﬁed as a global predicate—a Boolean expression whose value depends on the state of multiple processes and, perhaps,communication channels.Detecting global pred-icates involves identifying consistent global states[2],on which predicates are to be evaluated.In general,the num-ber of consistent global states is exponential in the num-ber of processes[5].Therefore an exhaustive search for all system states,which is necessary for detecting a general-form predicate,will suffer from the combinatorial explo-sion problem.Many researchers circumvent this problem by placing restriction on the types of predicates.In par-ticular,they have considered global predicates that can be logically decomposed into sub-expressions,each of which is locally detectable by a single process[13,11,3,8,15,9]. Such sub-predicates are called local predicates.Only lo-cal states upon which local predicates are satisﬁed have to be examined to see if any combination of them can form a consistent global state.The number of states examined istherefore reduced.A typical procedure toward this kind of predicate de-tection is as follows[3,8,9].Consider a distributed sys-tem that consists of processes,labeled.All processes cooperatively maintain vector clocks[6,12] which are used to timestamp events.This timestamping scheme possesses a desired property that for any two events and,we can determine if happens before[10](de-noted by)by comparing their timestamps.Once anevent upon which a local predicate is evaluated as true oc-curs,the process sends in FIFO order the event’s identiﬁca-tion together with its timestamp to a dedicated checker pro-cess[8,3].The checker process maintains event queues,,where each is for storing events from .Events in each queue are arranged in the order as they occurred:the head event of is the earliest predicate event among other events occurred in.The checker process performs two routines.Theﬁrstroutine examines if the event set comprising all current head events in each queue is consistent.The technique used in this routine is to repeatedlyﬁnd two causally related head events and remove the one that happened before the other [7,8].Whenever no event queue is empty and the checker cannot remove any head event,a consistent global predicate is identiﬁed.Events usually do not arrive at a constant rate,so it is possible that some event queue grows lengthily while oth-ers drain.If any event queue is empty,theﬁrst routine must wait for all absent events before it can proceed.Checker’s second routine identiﬁes and removes all events currently pending in queues that are evidently inconsistent with other not yet arrived events.Precluding useless events not only reduces space requirement on event queues,but also avoids further process of these events by theﬁrst routine.This re-moval does not impose additional computation overhead on the checker process:while theﬁrst routine cannot progress, the checker process can perform this routine rather than be-ing idle.In this paper,we focus on the design of this routine.Suppose that event queues are non-empty,each of which has events.A naive approach might involve look-ing at all possible sets consisting of one event from eachof the event queues[4].Chiou and Korfhage[4]pro-posed an algorithm forﬁnding removable events that has an time complexity.Their method,however,cannot identify all useless events.Although the necessary and suf-ﬁcient conditions for useless events have been formulated[14,1],as to the author’s knowledge,no practical algorithm has been proposed.Our method exploits the result in[1], which established the theory of event intervals,and treats the problem ofﬁnding useless events as an on-line compu-tation of a reachability matrix representing an event interval graph.We prevent unlimited expansion of the matrix by cut-ting down obsolete rows and columns,saving both memory space and execution time.The validity proof of our method is provided.The simulation result shows that our approach outperforms conventional approaches in the number of use-less events found.2.Preliminary2.1.DeﬁnitionsAn event upon which a local predicate is evaluated as true is deﬁned as a predicate event.Let denote the-th predicate event occurred at.Event interval is the set of all events between and,including but exclud-ing.1We deﬁne precedence relation between event intervals as follows.Deﬁnition1The direct precedence relation().Let and be two event intervals.if and only if(1) and or(2)there exists a message that is sent from some event in and is received by some event in.Deﬁnition2The precedence relation(denoted by)is the transitive closure of.We say that immediately precedes if, and that precedes if.A precedence graph is a directed graph,where is a set of event inter-vals,and iff.Figure1(b)shows the precedence graph corresponding to the sample execu-tion run in Figure1(a).2.2.Previous workNetzer and Xu[14]showed that an event cannot be in any consistent event set if and only if there is a zigzag pathWhether for any two successive event intervals and can then be determined by checking the exis-tence of a path from to in the precedence graph.However,when turning this conceptual result into a prac-tical on-line detection algorithm,we may encounter some difﬁculties.First,the checker process can construct only a subgraph of the complete precedence graph,which we de-ﬁne as constructed graph.Deﬁnition3A constructed graph is a sub-graph of a precedence graph in which the ver-tices are partitioned into two disjoint sets and such that for every and,if,then ,andfor every and,if,then andIntuitively,an event interval is in if all event intervals immediately preceding it,if any,are either in or in.An event interval is in if it is not in and it immediately precedes at least one event interval in.Constructed graph offers only partial information about precedence relation.For any two vertices and in a constructed graph,we have if there exists a path from to,but the reverse implication does not hold. Therefore,with a naive and straightforward algorithm de-sign,we may not reach a conclusion until the execution of the monitored program is completed,at which time the en-tire precedence graph is obtained.We overcame this difﬁ-culty by observing that the precedence relation is complete for all vertices in a particular subgraph of the precedence graph.This subgraph is deﬁned as explored graph.Deﬁnition4An explored graph is a sub-graph of a precedence graph with the property that for every and,if,then andLemma1An explored graph is a constructed graph with the property that.Theorem1Let and be any two vertices in an ex-plored graph.We have iff there exists a path from to in the explored graph.Proof:()Obvious.()implies that there is a path from to in the precedence graph.By the def-inition of explored graph,all vertices on this path together with all edges connecting them should also be in the ex-plored graph.So the same path exists in the explored graph.The second difﬁculty is the potentially expensive space and time cost.The constructed graph expands as new nodes and edges are gathered and accumulated,demand-ing a space size probably proportional to the execution time of the monitored program.Also,path computation time becomes longer as graph expands.Therefore,without an effective and efﬁcient way to prune the graph,only short-execution-time program can be debugged without suffering from performance degradation.Note that we cannot discard and associated incident edges just because is found to be removable(or,non-removable),since may be a node on some other cycles. We prune the constructed graph by remov-ing any subgraph that is an explored graphfrom it.The remaining graph is the induced subgraph of on the vertex set.This pruning scheme is re-peatedly performed to prevent the constructed graph from growing unlimitedly.After a subgraph has been identiﬁed as being an explored graph but before it is removed,we ex-amine every event interval in it to see if there exists a path from to.We claim that our graph-pruning scheme is safe.That is,it neither causes non-useless events to be wrongly identiﬁed as useless,nor does it hide any use-less events from being detected.Detailed proof is given in Section3.4.3.The proposed algorithmOur algorithm consists of two modules.Theﬁrst mod-ule,cooperatively executed by non-checker and checker processes,collects direct precedence relation information and forms the constructed graph.The second module iden-tiﬁes useless predicate events by examining the constructed graph,and prunes the graph by removing explored subgraph that has been completely examined.These two modules are not assumed to be executed in parallel:only one module can be activated at any instant of time.We do not prescribe any particular scheduling policy for them.3.1.Collecting direct precedence informationEach non-checker process locally tracks direct prece-dence relation resulted from the execution of the moni-tored program.The checker process collects pieces of di-rect precedence relation from all non-checker processes and assemble them into a constructed graph.The operation per-formed by each non-checker process is as follows(refer to Figure2).uses integer variable to count the number of predicate events detected at so far.An event interval(EI) tuple,which uniquely identiﬁes’s current event interval,,is attached to every application message sent es set variable to hold all incoming EI tu-ples.The contents of thus correspond to event intervals immediately preceding—EI tuple is in only if event interval immediately precedes.concludesFigure 2.Operations performed by non-checker processthe current event interval upon detecting a local predicate, at which time it sends as a debug message to the checker process.After that,is reset to,indi-cating that is the only event interval currently known to immediately precede the next one,and is then increased by one.3.2.Assembling constructed graphUpon receiving a debug message,the checker process invokes procedure updateitems and rowgraph operates as follows.Let the re-ceived message be.The procedureﬁrst adds a new column,,to matrix.It then examines each EI tuple in to see if it is necessary to add row to as well.The addition is not necessary ifalready exists or once existed but has been dis-carded(by our graph-pruning scheme,discussed later).In-teger array maxdiscarded records the maximal such that event intervals all have been discarded.Our graph-pruning scheme ensures that an event interval will not be discarded if any event in-terval preceding it has not yet been discarded.Soitems corresponds to the vertex set of the constructed graph.Also,the set cor-discarded for allrowitemsOn receivingadd a new column tocol itemsfor each EI tuple doif maxitems thenadd a new row torow itemsend ifend ifend forgraphresponding to the vertex set is row items rowremovable (Figure4)to perform two tasks:toﬁnd and remove use-less predicate events pending in event queues and to iden-tify and remove explored subgraph from the constructed graph.Theﬁrst task is done byﬁrst computing the transi-tive closure of and then checking whetherfor every in colitems rowitems that precede are also in colexplored in Figure4).Such is called an ex-plored event interval.All explored event intervals found are stored in set variable explored,and will be deleted one by one from the constructed graph.3.4.Proof of safetyIn this section,we shall prove that our graph-pruning scheme neither causes non-useless events to be wrongly identiﬁed as useless,nor does it hide any useless events from being detected.removable/*compute the transitive closure of*/for each colitems doif and rowitems doif then/*identify useless events and explored event intervals*/exploredfor each colexplored()then explored exploredif rowitems rowitems coldiscarded then maxexplored():Booleanfor each rowitems then return falseend forreturn trueend.removableFirst observe that propertyholds before any event interval has ever been discarded. Since each entry is either discarded or left un-changed but not modiﬁed,this property still holds after the ﬁrst event interval is discarded.It also holds after succes-sive removal of event intervals for the same reason.This implies that no predicate event will be wrongly identiﬁed as useless due to discarding explored event intervals.To prove that the graph-pruning scheme does not hide any useless events from being detected,we show that if is useless,then when is iden-tiﬁed as explored.Let denote the set of event intervals identiﬁed as explored in the-th invocation of procedure ﬁndremovable.The proof is divided into two steps.First we show that if is useless,im-plies that.Then we show that if, for any other event interval,implies that when is identiﬁed as explored.The following statements lead to theﬁrst step of the proof.If we do not discard any explored event intervals,the sufﬁcient condition for identifying that is explored, i.e.,is in colitems.This implication must be revised when we do discard explored event intervals.In such cases,some event intervals preceding may be discarded before is identi-ﬁed as explored.Therefore,the same sufﬁcient condition for identifying that is explored now implies that all event intervals preceding either are in colexplored can be de-scribed as follows.Theorem2colitems in the-th invocation.This necessity implies thatcolitems,then after the transitive closure of has been computed.Proof:The proof is by induction on.The claim triv-ially holds for.We assume that the claim holds for and consider the case of.Letbe an event interval chain such that has not yet been discarded and colitems.Just before the addition,we havecolitems.By Corol-lary2,had not been discarded at that time,since, the event interval immediately preceding,is not even received.By the induction hypothesis,this implies thatat that time.After the edgehas been added to the graph,having computed the transi-tive closure of ensures that for all such that and for all such that. Thus after the addition.It remains to be so as long as is not discarded and colitems and every that has not been discarded,if and,then there must be some such that and is not in colitems.Let be the maximal index of such event intervals.If we can show that,the proof is done.Observe that has not been discarded since is not even received.Also,colitems,if there exists no event interval such that andcolitems,if isitems,if isitems.By Corollary3, this implies that there exists no such that has not been discarded and,which in turn implies that for every that has not been discarded,.By Corollary1and Theorem5,it is clear that ifis useless,then when is identiﬁed as explored.So will be detected before discarding.4.Performance evaluation4.1.Time complexity analysisAssuming that the time to add a column or row is (which can be achieved if adding a column or row is in factPkP3P2P1Figure5.Scenario corresponding to worst-case explored graphadding a head of a linked list),the computation time of pro-cedure updategraph is therefore .Procedureﬁnditems rowexplored takes col items time.So the second loop,which identiﬁes explored event intervals and useless predicate events,takes col items computation time. The third loop obviously takes less computing time.We have thatﬁnd A is of col items time complexity.The values of col items depend on whether the constructed graph contains many small sub-graphs that are explored graphs.If it does,every time we execute procedureﬁnditems and rowitems and rowitems and rowremovable.The result obtained is for a single invocation of proce-dureﬁndsubgraph may not compensate the execution time imposed on.On the other hand,if we seldom invoke the procedure,the execution time may be terrible when we indeed execute it.The optimal solution cannot be obtained if we do not know in advance what the constructed graph will be.4.2.Simulation resultsIn this section,we evaluate the performance of our ap-proach by simulation.We assume a system consisting of ten processes.All processes but one randomly and inde-pendently generate predicate events,and report event in-tervals to the checker process in the order as they occur.The time interval between two consecutive predicate events is assumed to be an exponentially distributed random vari-able with mean .Each process randomly and indepen-dently sends messages,with destinations uniformly dis-tributed over all processes other than the sender.Message propagation delays and the time interval between two con-secutive sending events are both assumed to be exponen-tially distributed,with parametersand ,respectively.We varied the values of ,,and to represent various types of computation and communication patterns.We computed the ratio of predicate events identiﬁed use-less to the total.This is used as the metrics to compare our approach with the two methods proposed by Chiou and Korfhage,which are respectively denoted by C&K(A)and C&K(B).The difference between C&K(A)and C&K(B)is that the latter performs the same check repeatedly,rather than just once,until no further useless events can be found.Figures 6-9show some representativeresults.0%10% 20% 30% 40% 50% 60% 70% 80%5 10 15 20 25 30Mean time interval between two sending eventsR a t i o o f u s e l e s s e v e n t s (%)Figure 6.Results withandClearly,with a ﬁxed ,the ratio of useless predicate events decreases as the ratio increases (Figures 6and 7).This can be explained as follows.When ,many processes do not send out any application message between two consecutive predicate events,so zigzagcycles0%10% 20% 30% 40% 50% 60% 70% 80% 5 10 15 20 25 30Mean time interval between two predicate eventsR a t i o o f u s e l e s s e v e n t s (%)Figure 7.Results withandare unlikely to happen,and few useless events can be found.On the other hand,when,messages are likely to be sent between two consecutive predicate events,implying that zigzag cycles and thus useless events are more possible to occur.Mean message propagation delays ()also have impacts on the ratio of useless events.Generally,with aﬁxedsetting,the ratio of useless predicate events decreases as increases (Figures 8and 9).In all settings,our approach outperforms C&K(A)in terms of the number of useless events found.The perfor-mance of C&K(B)is between ours and C&K(A).When the ratio of useless events is high,C&K(B)is a match for our approach.But it degrades to C&K(A)when the ratio be-comes low.We also found that our graph-pruning technique does not help much in shrinking the size of .The reason is that we let one of all processes send messages but not report any predicate event.As a result,there did exist a large subgraph that cannot be divided into smaller explored subgraphs (i.e.,the one shown in Figure 5).That graph cannot be con-structed by the checker process and found to be explored,since there is always one event intervalabsent.0%10% 20% 30% 40% 5 10 15 20 25 30Mean message propagation delayR a t i o o f u s e l e s s e v e n t s (%)Figure 8.Results withand0%10% 20% 30% 40% 50% 60% 70% 80% 51015202530Mean message propagation delayR a t i o o f u s e l e s s e v e n t s (%)Figure 9.Results withand5.ConclusionsWe have proposed an approach that effectively precludes useless events for global predicate detection,facilitating the process of an independent on-line checking routine.To identify more useless events than a simple causality-check method can do,our method tracks and maintains the prece-dence information of event intervals as a graph.To re-duce the potentially expensive space and time cost as the graph expands,we have proposed a safe scheme to prune the graph.This scheme is safe in the sense that it neither causes non-useless events to be wrongly identiﬁed as use-less,nor does it hide any useless events from being detected.Suppose that event queues are non-empty,each ofwhich hasevents.Our approach takes com-putation time,while Chiou and Korfhage’s method takes.Our method,however,does not necessarily in-crease additional computation overhead on the checker pro-cess,since the checker process is otherwise idle.The sim-ulation result shows that our approach outperforms conven-tional approaches in terms of the number of useless events 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