Inventory Model with Seasonal Demand: A Specific Application to Haute Couture

In the stochastic multiperiod inventory problem, a vast majority of the literature deals with demand volume uncertainty. Other dimensions of uncertainty have generally been overlooked. In this paper, we develop a newsboy formulation for the aggregate multiperiod inventory problem intended for products of short sales season and without replenishments. A distinguishing characteristic of our formulation is that it takes a time dimension of demand uncertainty into account. The proposed model is particularly suitable for applications in haute couture, i.e., high fashion industry. The model determines the time of switching primary sales effort from one season to the next as well as optimal order quantity for each season with the objective of maximizing expected profit over the planning horizon. We also derive the optimality conditions for the time of switching primary sales effort and order quantity. Furthermore, we show that if time uncertainty and volume uncertainty are independent, order quantity becomes the main decision over the interval of the primary selling season. Finally, we demonstrate that the results from the two-season case can be directly extended to the multi-season case and the limited resource multiple-item case

Enhancing Revenue in College Sport Events by Practicing Yield Management and E-commerce

Many colleges and universities have been facing increasingly tight budgets in recent years and have been struggling to provide more funding for their own athletic programs. In some cases, specific sport programs of a college or university have had to be terminated due to lack of monies appropriated from the central administration. Yield or revenue management is a method of assigning capacity or inventory to meet demand in such a way to maximize revenue. This paper examines the feasibility and discusses the benefits of applying yield management via e-commerce to increase surplus/decrease deficit in those college sport programs where paid tickets are required for admissions, including, but not limited to, football and basketball games

Confining and hoop stresses in ring-confined thin-walled concrete-filled steel tube columns

Concrete-filled steel tube (CFST) columns are now widely adopted in many structures due to the superior behaviour provided by composite action. However, this composite action is limited because of the different dilation properties of the constitutive materials at the early elastic stage. Furthermore, due to inelastic outward buckling of the steel tube, CFST columns may suffer serious degradation of the steel confinement. To overcome these problems, external confinement in the form of rings has been recently studied, and test results have shown that such provision can improve the strength, elastic stiffness, ductility and interface bonding of CFST columns. In the work reported in this paper, as a continuation of a previous study of ring-confined CFST columns, ten concrete-filled thin-walled steel tubes were fabricated and tested under uniaxial compression. The main parameters examined were the concrete cylinder strength, the steel tube thickness and the ring spacing. The test results show that external rings are highly effective in improving the uniaxial behaviour of CFST columns. Based on the experimental hoop–axial strain relationships and Prandtl–Reuss theory for the steel tube, the true structural behaviour of unconfined and ring-confined CFST columns, such as the steel–concrete interface bonding condition, the behaviour of the steel tube and core concrete as well as the confining mechanisms, were explored

TEACHING AGGREGATE PLANNING IN OPERATIONS MANAGEMENT

This paper describes some unique characteristics of Aggregate Production Planning, which make the teaching of this topic in Operations Management courses somewhat different than other topics. A challenge when teaching Aggregate Planning is to make students understand the need to apply trial-and-error approaches to test, evaluate, and improve Aggregate Plans. In other words, do not just learn how to do the computations needed to develop an Aggregate Plan under certain conditions, but to actually analyze it and try to modify it with the objective of producing an improved plan. We recommend that in operations management courses, Aggregate Planning is taught within the context of a project, which includes a student individual element as well as a team component. The project involves the use of a spreadsheet, such as Microsoft Excel, to obtain Aggregate Plans with various input datasets and with different demand pattern and cost coefficients. It also requires each team to write a report discussing how the team derives its final plan and the insights acquired from the assignment. The paper starts with a compilation and description of unique features of Aggregate Planning, then it discusses the idea of using a students\u27 project when teaching this topic, and it finishes with an example. The paper also provides a couple of avenues for future research

PLAYING THE LOTTERY GAMES?

The lottery is a huge business. In 2011, $57.6 billion worth of lottery tickets were sold in 43 states and the District of Columbia. There are three major parties (governments, lottery players, and retailers) involved in the lottery industry, plus many more stakeholders. This paper examines the lottery from the viewpoints of these three primary parties. From the lottery players\u27 viewpoint, we show how to statistically determine the expected value of a lottery ticket and discuss when to conclude it is profitable to buy lottery tickets. We explore the question of whether lottery players are rational. State governments have, for years, relied on lottery money to fund education and other expenses. We examine the economic benefits as well as the societal costs of operating the lottery business. Finally, we examine the economics of selling lottery tickets from the retailers\u27 viewpoint

Opportunities in Green Supply Chain Management

The supply chain consists of those activities associated with manufacturing from raw material acquisition to final product delivery. Because of the recently changed environmental requirements that affect manufacturing operations and transportation systems, growing attention is given to the development of environment management strategies for supply chains. A green supply chain aims at confining the wastes within the industrial system so as to conserve energy and prevent the dissipation of harmful materials into the environment. In this paper, we compare and contrast the traditional and green supply chains. Moreover, we discuss several important opportunities in green supply chain management in depth, including those in manufacturing, bio-waste, construction, and packaging

Synthesis, Contact Printing, and Device Characterization of Ni-Catalyzed, Crystalline InAs Nanowires

InAs nanowires have been actively explored as the channel material for high performance transistors owing to their high electron mobility and ease of ohmic metal contact formation. The catalytic growth of non-epitaxial InAs nanowires, however, has often relied on the use of Au colloids which is non-CMOS compatible. Here, we demonstrate the successful synthesis of high yield of crystalline InAs nanowires with high yield and tunable diameters by using Ni nanoparticles as the catalyst material on amorphous SiO2 substrates. The nanowires show superb electrical properties with field-effect electron mobility ~2,700 cm2/Vs and ION/IOFF >103. The uniformity and purity of the grown InAs nanowires are further demonstrated by large-scale assembly of parallel arrays of nanowires on substrates via the contact printing process that enables high performance, printable transistors, capable of delivering 5-10 mA ON currents (~400 nanowires).Comment: 21 pages, 5 figures included, all in .docx format. Nano Research (In Press

Wafer-Scale Assembly of Semiconductor Nanowire Arrays by Contact Printing

Controlled and uniform assembly of "bottom-up" nanowire (NW) materials with high scalability has been one of the significant bottleneck challenges facing the potential integration of nanowires for both nano and macro electronic circuit applications. Many efforts have focused on tackling this challenge, and while significant progress has been made, still most presented approaches lack either the desired controllability in the positioning of nanowires or the needed uniformity over large scales. Here, we demonstrate wafer-scale assembly of highly ordered, dense, and regular arrays of NWs with high uniformity and reproducibility through a simple contact printing process. We demonstrate contact printing as a versatile strategy for direct transfer and controlled positioning of various NW materials into complex structural configurations on substrates. The assembled NW pitch is shown to be readily modulated through the surface chemical treatment of the receiver substrate, with the highest density approaching ~8 NW/um, ~95% directional alignment and wafer-scale uniformity. Furthermore, we demonstrate that our printing approach enables large-scale integration of NW arrays for various device structures on both Si and plastic substrates, with a controlled semiconductor channel width, and therefore ON current, ranging from a single NW (~10 nm) and up to ~250 um, consisting of a parallel array of over 1,250 NWs.Comment: 14 pages,4 figure

III–V Nanowires: Synthesis, Property Manipulations, and Device Applications

III–V semiconductor nanowire (NW) materials possess a combination of fascinating properties, including their tunable direct bandgap, high carrier mobility, excellent mechanical flexibility, and extraordinarily large surface-to-volume ratio, making them superior candidates for next generation electronics, photonics, and sensors, even possibly on flexible substrates. Understanding the synthesis, property manipulation, and device integration of these III–V NW materials is therefore crucial for their practical implementations. In this review, we present a comprehensive overview of the recent development in III–V NWs with the focus on their cost-effective synthesis, corresponding property control, and the relevant low-operating-power device applications. We will first introduce the synthesis methods and growth mechanisms of III–V NWs, emphasizing the low-cost solid-source chemical vapor deposition (SSCVD) technique, and then discuss the physical properties of III–V NWs with special attention on their dependences on several typical factors including the choice of catalysts, NW diameters, surface roughness, and surface decorations. After that, we present several different examples in the area of high-performance photovoltaics and low-power electronic circuit prototypes to further demonstrate the potential applications of these NW materials. Towards the end, we also make some remarks on the progress made and challenges remaining in the III–V NW research field

Hybrid core-multishell nanowire forests for electrical connector applications

Electrical connectors based on hybrid core-multishell nanowire forests that require low engagement forces are demonstrated. The physical binding and electrical connectivity of the nanowire electrical connectors arise from the van der Waals interactions between the conductive metallic shells of the engaged nanowire forests. Specifically, the nanofibrillar structure of the connectors causes an amplification of the contact area between the interpenetrating nanowire arrays, resulting in strong adhesion with relatively low interfacial resistance. The nanowire electrical connectors may enable the exploration of a wide range of applications involving reversible assembly of micro- and macroscale components with built-in electrical interfacing.open151