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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

以啟發式方法解決具迴流性質之彈性流程式排程問題 / Developing Heuristics for the Scheduling Problem With Recirculation on Flexible flow shop

陳俊吉, Chen, Chun Chi Unknown Date (has links)
由於網際網路的發展,使得全球環境變遷,競爭越來越激烈,企業必須面臨快速的需求變化,以及訂單履行時間縮短的問題,因此如何有效的利用生產規劃和現場排程來幫助企業達到較高的訂單達成率和即時反應現場產能一直是製造業努力的目標。 在排程的問題中,用派工法則來解決排程問題的工廠類型,主要集中在零工式生產系統及流程式生產系統,而進一步加入平行機器概念,即是彈性零工式生產及彈性流程式生產。而現在許多的服務業也都是屬於彈性流程式生產的模式,而且還具有迴流(recirculation)之性質,而之前使用在不具迴流性質之彈性流程式生產的派工法則,在具有迴流性質之彈性流程式生產中是否仍然可以表現良好,是值得探討的。然而更進一步在此具有迴流性質之彈性流程式生產中加入多工的性質,使工作可以被兩個或兩個以上的機器或操作人員進行處理,則運用哪個派工法則讓機器或操作人員選擇工作來進行處理,可以使得選定的目標值有良好的表現,是相當值得研究之問題。 / As information technology advances, whole world environmental trend and the competition is more and more intense. The enterprise must face faster demand changes and the problem of shorter order fulfillment. Therefore, how to apply efficient production planning and shop floor scheduling to attain a better order fulfillment and real time production of shop floor capacity is the goal enterprises strive toward. The shop floor scheduling problems using dispatching rules to solve are focus on job shop scheduling problems and flow shop scheduling problems. Moreover, those problems adding the concept of parallel machine will change into flexible job shop scheduling problems and flexible flow shop scheduling problems. Many service industries also belong to this type. In addition, those service industries’ processes also contain the important characteristic of recirculation. Now, there are two problems I would like to solve. First, Whether the dispatching rules which can get good results in flexible flow shop scheduling problems will also get good results in flexible flow shop scheduling problems with recirculation. Second, I add the characteristic of parallel machine into my problem, so it means jobs in the process can be operated by two or more workers. Therefore, which dispatching rule will get better results based on chosen achievement targets in the problem is very interesting to research.
2

基於QoS限制於SC-FDMA上行資源排程之研究 / Qos-Costrained Scheduling for Uplink SC-FDMA

李昀峻, Lee, Yun Jun Unknown Date (has links)
隨著無線通訊技術快速的發展,使用者對無線傳輸及品質的要求日益提升。第三代合作夥伴計劃3rd Generation Partnership Project (3GPP)所提出的長期演進技術Long Term Evolution (LTE),是邁入第四代行動通訊系統(4G)的極佳選擇。其中以Single Carrier - Frequency Division Multiple Access (SC-FDMA)系統作為上行鏈路的主要通信技術。 然而,在上行SC-FDMA中有連續性資源塊配置的規定以及所配置之資源塊需使用相同調變技術的限制。一般而言資源分配的好壞會影響傳輸速率(data rate)與系統效能。因此,如何分配資源以改善傳輸速率與增進系統效能是本論文的研究重點。 目前,已有許多文獻在探討如何透過偵測頻率響應(frequency response),解決資源分配的問題。但我們發現,透過偵測頻率響應的好壞進行優先權排班,無法有效符合現實網路服務的實際需求。在本論文中,我們擬以三階段的演算法來改善系統中資源分配的問題。第一階段,在time domain排班時根據不同的Quality of Service (QoS)特性區分User Equipment (UE)。在第二階段frequency domain排班時依據通道品質好壞決定優先權以分配無線電資源給UE。最後,我們根據SC-FDMA的兩大重要限制,提出在LTE上行系統中資源分配方法,在滿足Guaranteed Bit Rate (GBR)服務之時間延遲的限制時,亦能提升整體系統效能。 在模擬分析中,我們利用NS3進行模擬實驗分析,將我們所提出的三階段演算法在不同比例之網路服務類別的要求下,與固定子載波動態資源分配機制以及適應性動態子載波分配機制進行比較。實驗結果顯示,我們的方法在VoIP的average delay time相較於適應性動態分配法最多可改善約82.9%,real time gaming最多可改善約84.9%,而整體系統頻帶利用率(spectrum utilization)相較於固定與適應性分配機制最多可提升約15.3%。 / Long Term Evolution (LTE) is the latest standard of 3rd Generation Partnership Project (3GPP), which is one of the most promising technology for 4G mobile networks. The goal of LTE is to provide high data rate transmission, scalable bandwidth, low latency, and high-mobility. To achieve this goal, the LTE employs Orthogonal Frequency Division Multiplexing (OFDM) for downlink data transmission and Single Carrier - Frequency Division Multiple Access (SC-FDMA) for uplink transmission. This thesis focuses on the resource allocation problem of LTE SC-FDMA system. We propose a three-stage approach to improve resource allocation performance. In the first stage, we design a time domain scheduling according to different QoS features and time delay requirement to distinguish user equipment (UE). In the second stage, we design a frequency domain scheduling based on channel state information to give priorities to UEs. Finally, we propose resource allocation methods for LTE uplink under the two constraints of SC-FDMA. The proposed methods are proved to be able to meet the real-time service delay constraints and enhance overall system performance. In the simulations, the proposed three stage algorithms are compared to fixed sub-carrier dynamic resource allocation algorithm and adaptive dynamic sub-carrier algorithm against different proportions of network services. Simulation results show that our method outperforms the other two methods in terms of throughput, transmission delay and packet loss ratio.
3

多工作業多元性對工作團體績效與成員壓力反 應之影響:時間規劃的跨層次調節效果 / The Influence of Polychronicity Diversity on Work Group Performance and Group Members’ Stress: The Cross-Level Moderating Effect of Temporal Planning

何其霞, Ho, Chi-Hsia Unknown Date (has links)
在瞬息萬變的工作環境中,資訊量龐大而繁雜,工作團體成員自身的時間分配,影響著任務執行期間的團體運作。現代快速而多工的工作要求,團體成員的多工作業特徵顯得更為重要。有鑑於此,本研究以此為主題,同時探究多工作業多元性對團體表現與團體成員壓力之影響。而過去團體多元性研究即指出,多元性可能會同時具有正、反面影響,本研究嘗試探討多工作業多元性所形成之優劣,並進一步檢驗團體的時間規劃所可能扮演的跨層次調節角色,以知在甚麼情況下多工作業多元性能具有最大的效益。採用問卷法施測,蒐集了50份有效之團體成套問卷,包含192名全職工作者。結果發現,多工作業多元性有助於團體任務績效之表現,並在額外分析中發現了任務相依性的三階調節效果。在個體層次中,個體與團體之時間特徵差異會直接導致個體壓力與退縮反應,其中在高時間規劃情況下,此差異與個體壓力之關係會削弱。最後依據研究結果進行討論,並說明理論貢獻、實務意涵以及未來研究方向。 / Temporal individual differences are an under-explored, but research-worthy form of diversity in groups. This study examines how group temporal diversity–variation in members' polychronicity—can be effectively managed to maximize group performance. Besides, how this difference effect individual stress is also examined. Results from 50 work groups reveal that polychronicity diversity had a positive influence on task-oriented group performance. Additional analysis found that task interdependence moderated the interaction effect of temporal planning and polychronicity diversity on task-oriented group performance. In other hand, when individual and work group polychronicity were more incongruent, individual stress and withdrawal behavior increased. And the influence of the incongrunce on individual stress was less positive under conditions of stronger group temporal planning than under weaker group temporal planning. Results can be used to effectively compose groups in organizations and guide future group composition research.

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