Tool- and setup-constrained capacity -allocation problem with assignment restrictions

We address a shift-level production planning problem motivated by applications in the semiconductor industry. A number of jobs must be allocated among a number of non-identical parallel machines subject to constraints due to operational policy and resource requirements. The operational policy constraints are due to management policies, such as limiting the number of different setups on a machine during a shift. The resource constraints are due to the limited availability of secondary resources such as tooling needed to process a job at a machine. The objective is to assign the jobs to the machines in a manner that maximizes the total throughput of the machines, i.e., the total number of jobs processed over the planning horizon. We follow the approach of several industrial practitioners in decomposing this problem into two separate problems, that of allocating the work to the workcenters and that of sequencing the jobs on the individual machines, and focus our attention on the former. We first examine the computational complexity of this problem, relating it to a number of other problems in the literature and resolving the complexity of two open cases. After demonstrating that commercial integer programming software is unable to reliably solve even relatively small instances in short CPU times, we develop a number of polynomial-time constructive heuristics and derive analytical worst-case performance bounds for two of these. Extensive computational experiments on randomly generated test problems indicate that the heuristics perform very well, both on average and in the worst case. We then proceed to develop a scheme for local improvement heuristic, which further improves upon the performance of the constructive heuristics. Finally, we explore exact solution procedures for the problem, examining the performance of different lower bounds as well as several different heuristic branching rules. While we are able to match the performance of the commercial software in some cases, we are unable to significantly improve over it in others. We conclude that the development of consistently effective exact solution methods is a difficult task due to the inherent degeneracy of the problem, and discuss a number of avenues for future research

Analyzing the effects of inventory cost setting rules in a disassembly and recovery environment

In this study we consider a disassembly and recovery facility receiving end-of-life products and facing demand for a specific part that is disassembled from the product and then recovered. The disassembly and recovery operations can be either performed before hand, or upon customer arrival. In the latter case, a discount on the selling price is applied to compensate the customer for waiting for the completion of the disassembly and recovery operations. One of the dificulties faced in planning for such a system is the determination of the opportunity cost associated with carrying recovered parts inventory. The dificulty arises in seeking the value added to the part given the costs incurred for maintaining the product return, disassembly and recovery costs and revenue earned from the hulk, that is the remaining product after the disassembly of the part. The main objective of the study is to investigate the effect of different rules to determine this opportunity cost on the performance of the system. Six rules are considered in the study. The performance of the rules is assessed by a computational study under an approximate inventory control policy

Effects of random yield in remanufacturing with price-sensitive supply and demand

In this study, we investigate the effects of recovery yield rate on pricing decisions in reverse supply chains. Motivated by the automotive parts remanufacturing industry, we consider an end-of-life product from which a particular part can be recovered and remanufactured for reuse, and the remainder of the product can be recycled for material recovery. Both the supply of end-of-life products and demand for remanufactured parts are price-sensitive. Yield of the recovery process is random and depends on the acquisition price offered for the end-of-life products. In this setting, we develop models to determine the optimal acquisition price for the end-of-life products and the selling price for remanufactured parts. We also analyze the effects of yield variation to the profitability of remanufacturing, benefits of delaying pricing decisions until after yield realization, and value of perfect yield rate information

Analyzing the Effects of Inventory Cost Setting Rules in a Disassembly and Recovery Environment

We consider a salvaging facility that satisfies the demand for remanufactured parts that can be recovered from the end-of-life products. One of the difficulties faced in planning for such a system is the determination of the opportunity cost associated with carrying recovered parts inventory. In this study we investigate the effect of different rules to determine this opportunity cost on the performance of the system. The performance of several different rules is assessed by a computational study under a proposed approximate inventory control policy

Part Recovery under Quality and Demand Uncertainty with Environmental Costs

We consider acquisition and stocking decisions, motivated by the operations of a salvaging facility that collects a particular end-of-life product, performs a series of disassembly and recovery operations to reclaim a reusable part and sells the recovered part in the used parts market. We model uncertainties in demand and quality classification of the parts and include environmental fees that create a non-negligible tradeoff against the operational costs in acquisition and stocking decisions

Disassembly and Recovery Planning for a Salvaging Facility

Stochastic inventory models are investigated for a salvaging facility that disassembles a type of end-of-life product for recovery. A single-period newsvendor type of setting is considered to capture the basic tradeoffs between unit cost and revenue structures under three different product structure and recovery operation schemes. A numerical study is conducted to analyze the effects of dependencies due to product and recovery operation structures

Two Balloons Can Fly a Minaret: Parody and Fabricated Reality as Integral Qualities of Mock-Documentary in <i>aya Seyahat</I>

This paper takes a close look at the critically acclaimed artist and filmmaker Kutlu & gbreve; Ataman's mockumentary Aya Seyahat (Journey to the Moon, 2009). We discuss the potentials and possibilities that the mockumentary mode brings to the film in detail, and address this mode as an aesthetic and critical manner that Ataman employs in his artistic practice. Through this discussion, we evaluate the ways in which the film is informed by and can be interpreted as a parodic observation of recurrent patterns in Turkish politics and representations of the national pasts. We argue that it exemplifies and endorses mockumentary's politically reflexive capacity to rethink history and the process of historiography in which historical truths are constructed. Mockumentary mode offers layers of meanings, exceeding the obvious narrative of historical parody, and invites the viewers to notice and problematize conventional narrational and stylistic methods of documenting a historical event. Thus, the film provides a criticism and comparison of the public opinion towards politics within two distinct periods in Turkey's history, namely the 1950s and the 2000s. It also opens up a space for a critical engagement with Turkey's troubled pasts and their construction as historical narratives in both cinematic and other representations.Emerging Sources Citation Inde

Hyperbaric oxygen therapy for carbon monoxide poisoning

Carbon monoxide poisoning is a life-threatening poisoning. In this case report neurological findings developed in carbon monoxide poisoning and the importance of multidisciplinary approach are discussed. The patient, 16-year-old male, was found unconscious following a 1-hour exposure to gas water heater poisoning and brought to our hospital after being intubated at the scene of the accident. After treatment for bicarbonate deficit, hepatamine infusion was started and hyperbaric oxygen treatment was performed. The patient was connected to mechanical ventilator in our department. The treatment were performed for cerebral edema. And hyperbaric oxygen treatment continued for 12 days. The patient was disconnected from the ventilator on the 36 th day of the follow-up. Medical history and clinical examination are very important in the diagnosis of carbon monoxide poisoning. The patient should be followed up with laboratory examinations and imaging methods such as magnetic resonance imaging in order not to overlook neurological sequelae or any organ injury. Additionally hyperbaric oxygen treatment performed in acute period and goal-directed therapy decrease mortality and morbidity