Order picking operations play a critical role in the order fulfillment process of distribution centers (DCs). Picking a batch of orders is often favored when customers’ demands create a large number of small orders, since the traditional single-order picking process results in low utilization of order pickers and significant operational costs. Specifically, batch picking improves order picking performance by consolidating multiple orders in a "batch" to reduce the number of trips and total travel distance required to retrieve the items. As more pickers are added to meet increased demand, order picking performance is likely to decline due to significant picker blocking. However, in batch picking, the process of assigning orders to particular batches allows additional flexibility to reduce picker blocking. This dissertation aims to identify, analyze, and control, or mitigate, picker blocking while batch picking in picker-to-part systems. We first develop a large-scale proximity-batching procedure that can enhance the solution quality of traditional batching models to near-optimality as measured by travel distance. Through simulation studies, picker blocking is quantified. The results illustrate: a) a complex relationship between picker blocking and batch formation; and b) a significant productivity loss due to picker blocking. Based on our analysis, we develop additional analytical and simulation models to investigate the effects of picker blocking in batch picking and to identify the picking, batching, and sorting strategies that reduce congestion. A new batching model (called Indexed order Batching Model (IBM)) is proposed to consider both order proximity and picker blocking to optimize the total order picking time. We also apply the proposed approach to bucket brigade picking systems where hand-off delay as well as picker blocking must be considered. The research offers new insights about picker blocking in batch picking operations, develops batch picking models, and provides complete control procedures for large-scale, dynamic batch picking situations. The twin goals of added flexibility and reduced costs are highlighted throughout the analysis.

Organic light-emitting Diode (OLED) emits light itself. It owns many advantages of optical-electronic characteristics as compared with Thin Films Transistor-Liquid Crystal Display (TFT-LCD). In order to achieve the requirement for full color flat panel display, the three primary colors which are red, green, blue (R,G,B) with high luminance¡Bhigh current efficiency¡Band high color purity are important study of research and development for OLED. In our experiment, the major materials are NPB¡BDPVBi¡BAlq3¡BLiF¡BPBD¡BDCJTB¡FThe materials of NPB¡BDPVBi¡BAlq3,LiF is used as hole transporting layer¡Bblue emission layer¡Belectron transporting layer, and electron injection layer, respectively. PBD is hole-blocking layer and DCJTB is red emission layer which is intended to indirectly demonstrate the hole-blocking effect in the interface between NPB and DPVBi layer. The blue light emission with short wavelength plays an important role in color conversion method (CCM) of full color technology. In the study, we improve and research on color purity of blue OLED by various thicknesses of organic layer. In addition, we research the influence of the device with different thicknesses of PBD layer as hole-blocking layer. In order to improve the color mixing phenomenon, we add extra DPVBi layer to the device with PBD layer. It can improve the blue color purity and obtain narrower full width at half maximum (FWHM).

No description available.

Bargaining theory seeks to answer the question of how to divide a jointly generated surplus between multiple agents. John Nash proposed the Nash Bargaining Solution to answer this question for the special case of two agents. Kleinberg and Tardos extended this idea to network games, and introduced a model they call the Bargaining Game. They search for surplus divisions with a notion of fairness, defined as balanced solutions, that follow the Nash Bargaining Solution for all contracting agents. Unfortunately, many networks exist where no balanced solution can be found, which we call unstable. In this thesis, we explore methods of changing unstable network structures to find fair bargaining solutions. We define the concept of Blocking Sets, introduced by Biro, Kern and Paulusma, and use them to create stability. We show that by removing a blocking set from an unstable network, we can find a balanced bargaining division in polynomial time. This motivates the search for minimal blocking sets. Unfortunately this problem is NP-hard, and hence no known efficient algorithm exists for solving it. To overcome this hardness, we consider the problem when restricted to special graph classes. We introduce a O(1)-factor approximation algorithm for the problem on planar graphs with unit edge weights. We then provide an algorithm to solve the problem optimally in graphs of bounded treewidth, which generalize trees.

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 26, 2008) Includes bibliographical references.

Thesis (Ph. D.)--Massachusetts Institute of Technology, 1984. / Includes bibliographical references (p. 127-135).

Electrical energy is an essential resource for the modern world. Unfortunately, its price has almost doubled in the last decade. Furthermore, energy production is also currently one of the primary sources of pollution. These concerns are becoming more important in data-centers. As more computational power is required to serve hundreds of millions of users, bigger data-centers are becoming necessary. This results in higher electrical energy consumption. Of all the energy used in data- centers, including power distribution units, lights, and cooling, computer hardware consumes as much as 80%. Consequently, there is opportunity to make data-centers more energy efficient by designing systems with lower energy footprint. Consuming less energy is critical not only in data-centers. It is also important in mobile devices where battery-based energy is a scarce resource. Reducing the energy consumption of these devices will allow them to last longer and re-charge less frequently. Saving energy in computer systems is a challenging problem. Improving a sys- tem’s energy efficiency usually comes at the cost of compromises in other areas such as performance or reliability. In the case of secondary storage, for example, spinning-down the disks to save energy can incur high latencies if they are accessed while in this state. The challenge is to be able to increase the energy efficiency while keeping the system as reliable and responsive as before. This thesis tackles the problem of improving energy efficiency in existing systems while reducing the impact on performance. First, we propose a new technique to achieve fine grained energy proportionality in multi-disk systems; Second, we design and implement an energy-efficient cache system using flash memory that increases disk idleness to save energy; Finally, we identify and explore solutions for the page fetch-before-update problem in caching systems that can: (a) control better I/O traffic to secondary storage and (b) provide critical performance improvement for energy efficient systems.

This dissertation describes the single-molecule magnet (SMM) behaviour of f-block cyclooctatetraenyl sandwich complexes. Chapter one introduces the concepts that dictate SMM behavior particularly in f-elements. The emphasis is to understand the origin of magnetic behaviour and the properties that make lanthanide elements particularly interesting to explore. Current strategies used to predict such behaviour are discussed and a literature review on the subject is provided. Chapter Two describes the magnetic properties of eight isostructural lanthanide sandwich complexes utilizing 1,4-bis(trimethylsilyl)cyclooctatetraenyl dianion as the ligand, [Li(DME)3][LnIII(COT”)2] (Ln = Ce, Nd, Gd, Tb, Dy, Ho, Er, Tb, COT” = 1,4-bis(trimethylsilyl)cyclooctatetraenyl dianion, DME = dimethoxyethane). The complexes display a wide range of magnetic behaviour. The best performing SMM was the erbium complex, which had a blocking temperature of 8 K. Investigating different lanthanide ions with the same ligand enabled us to evaluate our findings in relation to current models used to predict SMM behaviour in lanthanide complexes. Chapter three extends the discussion of lanthanide sandwich complexes to include higher symmetry cyclooctatetraenyl complexes of ErIII and DyIII, [K(18-C-6)][LnIII(COT)2] (18-C-6 = 1,4,7,10,13,16-hexaoxacyclooctadecane, COT = cyclooctatetraene).The change in symmetry evoked by removing the trimethylsyl- (TMS) groups on the ligand greatly influenced the magnetic properties of both complexes. Ab initio calculations revealed that the magnetic relaxation in the ErIII complex occurs via the second excited state which contributes to the very high blocking temperature of 10 K in this complex. Chapter four presents an organometallic building block approach to create triple decker lanthanide COT” complexes of GdIII, DyIII and ErIII with a molecular formula of LnIII2(COT”)3. Synthetically, we couple together the sandwich complexes discussed in Chapter 2 by oxidatively removing one ligand to produce linear complexes where the two metals are bridged by an aromatic COT” ligand. The magnetic properties of all complexes are compared to their respective mononuclear analogs. Most interesting is the unprecedented 4 K increase in blocking temperature of the triple decker ErIII analog compared to the ErIII mononuclear sandwich complex discussed in Chapter 2. This increase is due to a ferromagnetic dipole-dipole interaction between the ErIII ions through the COT” ring. The aromatic bridging ligand provides a GdIII - GdIII interaction of J = -0.448(1) cm-1. Chapter five extends the discussion of magnetic exchange coupling to include linear K2(THF)4[LnIII2(COT)4] (Ln = Gd, Dy, Er, COT = cyclooctatetraenyl dianion, THF = tetrahydrofuran) complexes of GdIII, DyIII and ErIII. Each complex is composed of two LnCOT2 units bridged linearly by a potassium ion. The magnetic interaction between metal ions is much weaker than in the triple decker complexes discussed in Chapter 4, with a GdIII-GdIII interaction of J = − 0.007(4) cm–1. The magnetic properties of the quadruple decker complexes were compared to their mononuclear equivalents (Chapter 3). Surprisingly, the ErIII complex showed an increase in magnetic blocking temperature over its mononuclear analog despite the large ErIII-ErIII separation of 8.819 Å. Ab initio calculations revealed that this increase is due to single ion effects, most likely an increase in symmetry. Chapter six deviates from lanthanide magnetism to study the magnetic properties of uranium sandwich complexes with multiple ligand systems and oxidation states. Prior to this study the SMM behaviour of uranium sandwich complexes was unknown. We report the synthesis, structure and magnetic properties of both uranium-COT” sandwich complexes and uranium-cycloheptatrienyl complexes with oxidation states spanning (III)-(V). None of the complexes showed zero-field SMM behaviour, indicating a sandwichtype ligand is not appropriate for harnessing the SMM character in uranium. We compared the slow magnetic relaxation of isostructural and valence isoelectronic uranium and neodymium complexes. The improved energy barrier in the uranium complex further motivates the use of uranium in SMM design due to its large spin-orbit coupling.

Exposure to misleading post-event information can result in impaired memory for the original event. Two theoretical mechanisms (i.e., retrieval blocking and source misattribution) have been proposed as explanantions for the occurrence of the misinformation effect. The impact of context on the occurrence of these errors has been examined to determine if changing the context between events reduces the misinformation effect. Previous findings indicate that context plays a different role in each of these mechanisms; however, experimental differences in the paradgms used to examine retrieval blocking and source misattribution have made comparisons between these mechanisms difficult. The present study examined the role of context in eyewitness memory using the same materials, manipulations, and procedures to determine if context does, in fact, have a different impact on these mechanisms. Results indicate that changing the context between events reduces the occurrence of source misattribution but does not ameliorate the impact of retrieval blocking.

According to the misinformation effect, exposure to misleading post-event information typically impairs memory for the original event. Such findings are generally obtained in the laboratory using the misinformation paradigm. One component of the typical misinformation paradigm is that most of the post-event information corresponds with the event information, implying that the context surrounding the misinformation is the same as that of the original event. The present experiments investigated the role of such implication by presenting the experimental conditions with misleading items in a narrative that differed from the original event (a slide show) to varying degrees; both the location of the event and the persons described were varied. A significant misinformation effect was obtained regardless of implication condition. Even when a relationship between the witnessed event and post-event narrative was not implied, memory was impaired by the presence of misleading information. The findings are discussed in terms of retrieval blocking.