Guided vehicles (GVs) are commonly used for the internal transportation of loads in warehouses, production plants and terminals. These guided vehicles can be routed with a variety of vehicle dispatching rules in an attempt to meet performance criteria such as minimizing the average load waiting times. In this research, we use simulation models of three companies to evaluate the performance of several real-time vehicle dispatching rules, in part described in the literature. It appears that there is a clear difference in average load waiting time between the different dispatching rules in the different environments. Simple rules, based on load and vehicle proximity (distance-based) perform BEST for all cases. The penalty for this is a relatively high maximum load waiting time. A distance-based rule with time truncation, giving more priority to loads that have to wait longer than a time threshold, appears to yield the BEST possible overall performance. A rule that particularly considers load-waiting time performs poor overall. We also show that using little pre-arrival information of loads leads to a significant improvement in the performance of the dispatching rules without changing their performance ranking.
標簽： Testing and classifying vehicle dispatching rules in three real-world settings
上傳時間： 2016-04-01
上傳用戶：五塊錢的油條
Abstract—In the future communication applications, users may obtain their messages that have different importance levels distributively from several available sources, such as distributed storage or even devices belonging to other users. This scenario is the BEST modeled by the multilevel diversity coding systems (MDCS). To achieve perfect (information-theoretic) secrecy against wiretap channels, this paper investigates the fundamental limits on the secure rate region of the asymmetric MDCS (AMDCS), which include the symmetric case as a special case. Threshold perfect secrecy is added to the AMDCS model. The eavesdropper may have access to any one but not more than one subset of the channels but know nothing about the sources, as long as the size of the subset is not above the security level. The question of whether superposition (source separation) coding is optimal for such an AMDCS with threshold perfect secrecy is answered. A class of secure AMDCS (S-AMDCS) with an arbitrary number of encoders is solved, and it is shown that linear codes are optimal for this class of instances. However, in contrast with the secure symmetric MDCS, superposition is shown to be not optimal for S-AMDCS in general. In addition, necessary conditions on the existence of a secrecy key are determined as a design guideline.
標簽： Fundamental Limits Secure Class on of
上傳時間： 2020-01-04
上傳用戶：kddlas
I saw the light of the future when I first read Ray Kurzweil’s BEST-seller book The Singularity Is Near: When Humans Transcend Biology. One cubic inch of nanotube cir- cuitry, once fully developed, would be up to one hundred million times more powerful than the human brain.
標簽： Predictive Cognitive Warning System Early The
上傳時間： 2020-05-26
上傳用戶：shancjb
Without conceding a blemish in the first edition, I think I had BEST come clean and admit that I embarked on a second edition largely to adopt a more geometric approach to the detection of signals in white Gaussian noise. Equally rigorous, yet more intuitive, this approach is not only student-friendly, but also extends more easily to the detection problem with random parameters and to the radar problem
標簽： Communication Foundation Digital in
上傳時間： 2020-05-26
上傳用戶：shancjb
The dictionary definition of telecommunications is ‘communication over long distance by cable, telegraph, telephone or broadcasting’, but since its initiation over 100yearsagothingshavemovedrapidly.Telecommunicationsisnowaverycomplex industrywithmanydifferentpressures,operatinginahighlydynamic environment.It is BEST viewed as part of a wider industry known as information and communication technology (ICT). The purpose of this chapter is to explain where telecommunication fits in, to highlight some of the complexities – hopefully to simplify them – and to position the industry in today’s dynamic business environment.
標簽： Telecommunications Understanding Business
上傳時間： 2020-06-01
上傳用戶：shancjb
As a student I did my BEST to avoid text books – a strange statement for a Professor to make and one that I should clarify before you put this book down; I did my BEST to avoid text books that did not help me.
標簽： Microdevices Ceramic Thick Films MEMS for and
上傳時間： 2020-06-06
上傳用戶：shancjb
Recent advancements in nanotechnology (NT) materials and growth of micro/ nanotechnology have opened the door for potential applications of microelectro- mechanical systems (MEMS)- and NT-based sensors and devices. Such sensors and devices are BEST suited for communications, medical diagnosis, commercial, military, aerospace, and satellite applications. This book comes at a time when the future and well-being of Western industrial nations in the twenty-first century’s global eco- nomy increasingly depend on the quality and depth of the technological innovations they can commercialize at a rapid pace.
標簽： MEMS
上傳時間： 2020-06-06
上傳用戶：shancjb
The term “ smart grid ” defi nes a self - healing network equipped with dynamic optimiza- tion techniques that use real - time measurements to minimize network losses, maintain voltage levels, increase reliability, and improve asset management. The operational data collected by the smart grid and its sub - systems will allow system operators to rapidly identify the BEST strategy to secure against attacks, vulnerability, and so on, caused by various contingencies. However, the smart grid fi rst depends upon identifying and researching key performance measures, designing and testing appropriate tools, and developing the proper education curriculum to equip current and future personnel with the knowledge and skills for deployment of this highly advanced system.
上傳時間： 2020-06-07
上傳用戶：shancjb
It all started rather innocuously. I walked into Dr GT Murthy’s office one fine day, andchanged my life. “Doc” was then the General Manager, Central R&D, of a very largeelectrical company headquartered in Bombay. In his new state-of-the-art electronics center,he had hand-picked some of India’s BEST engineers (over a hundred already) ever assembledunder one roof. Luckily, he too was originally a Physicist, and that certainly helped me gainsome empathy. Nowadays he is in retirement, but I will always remember him as athoroughly fair, honest and facts-oriented person, who led by example. There were severalthings I absorbed from him that are very much part of my basic engineering persona today.You can certainly look upon this book as an extension of what Doc started many years agoin India … because that’s what it really is! I certainly wouldn’t be here today if I hadn’t metDoc. And in fact, several of the brash, high-flying managers I’ve met in recent years,desperately need some sort of crash course in technology and human values from Doc!
標簽： 開關電源
上傳時間： 2021-11-23
上傳用戶：
網絡安全技術-QoS技術白皮書摘 要：本文對Internet的三種服務模型（BEST-Effort、IntServ和DiffServ），以及服務模型的 發展歷程進行了簡單介紹，較為詳細地介紹了H3C系列數據通信產品所支持的QoS技 術，內容包括：流量分類和標記、擁塞管理、擁塞避免、流量監管與流量整形、鏈路 效率機制以及MPLS網絡相關QoS技術，并且簡要描述了在實際應用中的QoS解決方 案。網絡運營商及行業用戶等通過對這些QoS技術的靈活運用，可以在Internet或任何 基于IP的網絡上為客戶提供有保證的區分服務。1 概述 1.1 產生背景 在傳統的IP網絡中，所有的報文都被無區別的等同對待，每個轉發設備對所有的報 文均采用先入先出（FIFO）的策略進行處理，它盡最大的努力（BEST-Effort）將報 文送到目的地，但對報文傳送的可靠性、傳送延遲等性能不提供任何保證。 網絡發展日新月異，隨著IP網絡上新應用的不斷出現，對IP網絡的服務質量也提出 了新的要求，例如VoIP等實時業務就對報文的傳輸延遲提出了較高要求，如果報 文傳送延時太長，用戶將不能接受（相對而言，E-Mail和FTP業務對時間延遲并不 敏感）。為了支持具有不同服務需求的語音、視頻以及數據等業務，要求網絡能夠 區分出不同的通信，進而為之提供相應的服務。傳統IP網絡的盡力服務不可能識別 和區分出網絡中的各種通信類別，而具備通信類別的區分能力正是為不同的通信提 供不同服務的前提，所以說傳統網絡的盡力服務模式已不能滿足應用的需要。 QoS技術的出現便致力于解決這個問題。 1.2 技術優點 QoS旨在針對各種應用的不同需求，為其提供不同的服務質量。如： z 可以限制骨干網上 FTP 使用的帶寬，也可以給數據庫訪問以較高優先級。 z 對于 ISP，其用戶可能傳送語音、視頻或其他實時業務，QoS 使 ISP 能區分 這些不同的報文，并提供不同服務。 z 可以為時間敏感的多媒體業務提供帶寬和低時延保證
上傳時間： 2022-02-26
上傳用戶：kingwide
