1,167 research outputs found

    Efficiency Predictions by Fuzzy Piecewise Auto-regression in Dynamic Network System

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    Workshop 2015 -Advances in DEA Theory and Applications (December 1-2, 2015)Since efficiency prediction can help managers to monitor future performance and detect potential failures, it is important for production and operation management. Data envelopment analysis is comprehensively applied to evaluate the relative performance in various areas. However, only few studies try to forecast the relative performance estimated by data envelopment analysis. We propose a performance forecasting model that integrates the multi-activity dynamic network data envelopment analysis and fuzzy piecewise auto-regression. The proposed approach constructs a dynamic performance measurement with the network structure to calculate the catching-up efficiency index. The catching-up efficiency index is further decomposed into the technical efficiency change and dynamic efficiency change to capture the effect of carry-over items. The fuzzy piecewise auto-regression is applied to regress the possibility and necessity estimation models by catching-up efficiency index for forecasting efficiency. In this paper, a data from banks in Taiwan from 2006 to 2012 are applied. The results indicate that the proposed approach has highly accuracy rate.The workshop is supported by JSPS (Japan Society for the Promotion of Science), Grant-in-Aid for Scientific Research (B), #25282090, titled “Studies in Theory and Applications of DEA for Forecasting Purpose.本研究はJSPS科研費 基盤研究(B) 25282090の助成を受けたものです

    OPTIMAL INBOUND/OUTBOUND PRICING MODEL FOR REMANUFACTURING IN A CLOSED-LOOP SUPPLY CHAIN

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    The paper presents a model for optimizing inbound and outbound pricing for closed-loop supply chains that remanufacture reusable products. Remanufacturers create reusable products from returned used products and sell the products “as new” to manufacturers or consumers. By implementing a return subsidy, remanufacturers can encourage the consumer to return used products. Demand for the as-new components often depends on the selling price and inventory. The available inventory increases as the subsidy increases and as the price decreases. Our model can determine the optimal subsidy and selling price for used and remanufactured products, respectively. Our model uses the Karush–Kuhn–Tucker conditions to solve its nonlinear problem. Sensitivity analysis reveals how different parameters affect profit under model-optimized conditions

    Measuring the Relative Efficiency of IC Design Firms: A Directional Distance Functions and Meta-Frontier Approach

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    An alternative approach for evaluating the efficiency of integrated circuit (IC) design firms is presented in this paper. We took into account the differences between technology groups, containing one or more design firms, and input and output factors to prevent influences of scale (e.g., firm size). Specifically, we employed a directional distance function approach to data envelopment analysis in order to evaluate inefficiency scores and differences among groups based on input and output factors. We found the efficiency of Taiwan’s IC design firms to be dependent not only on firm size but also on R&D expenditure and patent revenue. Our findings suggest that these factors significantly influenced the technical efficiency of Taiwan IC design. Furthermore, by focusing on technology gaps, we offer some suggestions for the different groups based on group-frontier and meta-frontier analyses. Finally, using the results of these analyses, we extended the global results of this study, presenting ways to further improve their efficiency

    Ischemic conditioning by short periods of reperfusion attenuates renal ischemia/reperfusion induced apoptosis and autophagy in the rat

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    Prolonged ischemia amplified iscehemia/reperfusion (IR) induced renal apoptosis and autophagy. We hypothesize that ischemic conditioning (IC) by a briefly intermittent reperfusion during a prolonged ischemic phase may ameliorate IR induced renal dysfunction. We evaluated the antioxidant/oxidant mechanism, autophagy and apoptosis in the uninephrectomized Wistar rats subjected to sham control, 4 stages of 15-min IC (I15 × 4), 2 stages of 30-min IC (I30 × 2), and total 60-min ischema (I60) in the kidney followed by 4 or 24 hours of reperfusion. By use of ATP assay, monitoring O2-. amounts, autophagy and apoptosis analysis of rat kidneys, I60 followed by 4 hours of reperfusion decreased renal ATP and enhanced reactive oxygen species (ROS) level and proapoptotic and autophagic mechanisms, including enhanced Bax/Bcl-2 ratio, cytochrome C release, active caspase 3, poly-(ADP-ribose)-polymerase (PARP) degradation fragments, microtubule-associated protein light chain 3 (LC3) and Beclin-1 expression and subsequently tubular apoptosis and autophagy associated with elevated blood urea nitrogen and creatinine level. I30 × 2, not I15 × 4 decreased ROS production and cytochrome C release, increased Manganese superoxide dismutase (MnSOD), Copper-Zn superoxide dismutase (CuZnSOD) and catalase expression and provided a more efficient protection than I60 against IR induced tubular apoptosis and autophagy and blood urea nitrogen and creatinine level. We conclude that 60-min renal ischemia enhanced renal tubular oxidative stress, proapoptosis and autophagy in the rat kidneys. Two stages of 30-min ischemia with 3-min reperfusion significantly preserved renal ATP content, increased antioxidant defense mechanisms and decreased ischemia/reperfusion enhanced renal tubular oxidative stress, cytosolic cytochrome C release, proapoptosis and autophagy in rat kidneys

    A Study on the Management Effectiveness and Problems of Tribal Colleges in Taiwan

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    The main purpose of this study is to analyze the development background and objectives of indigenous tribal colleges, and to understand the effectiveness and problems of its management in Taiwan. After SWOT analysis, the main findings are as follows: 1. Advantages: the unique culture of indigenous people is an opportunity for economic development. In addition, the protection of laws and regulations is the main advantage of tribal college. 2. Weakness: under the current economic system, the indigenous people are limited in land use, inconvenient transportation, inadequate agricultural technology, and unsmooth sales channels, which limit their economic development. 3. Threats: because the population flows to the city, the tribal people do not understand what kind of institution the tribal university is, and some of the funds have to be paid by the learners themselves, resulting in the low participation of the tribal people. Moreover, the units that handle tribal college are almost different every year, which affects the preservation of data. 4. Opportunities: the existence of tribal college also provides an opportunity for the inheritance and reconstruction of indigenous culture. Based on the above analysis, this study puts forward relevant suggestions for the management of tribal colleg

    Prevalence of Helicobacter pylori Infection in High-school Students on Lanyu Island, Taiwan: Risk Factor Analysis and Effect on Growth

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    Background/PurposeThe Yami inhabit Lanyu Island and are the smallest and most primitive aboriginal tribe in Taiwan. Lanyu Island is a closed environment and little information is available on the prevalence of Helicobacter pylori infection there. This study aimed to establish the prevalence of H. pylori infection in high-school students on Lanyu Island and its risk factors and effect on growth.MethodsA cross-sectional population-based study was conducted among high-school students to determine the prevalence of H. pylori infection by using the 13C urea breath test. A questionnaire was administered to the recruited population. Relevant personal and socioeconomic data for risk factors of infection were collected. Body height and weight of the recruited adolescents in relation to H. pylori infection were analyzed.ResultsA total of 106 high-school students (55 boys and 51 girls), with a mean age of 14.3 ± 1.4 years were enrolled. The overall prevalence of H. pylori infection was 54.7%. Those residing in Dongcing village had the highest rate of H. pylori infection (73.3%). There was no difference in the prevalence of H. pylori infection according to sex, ethnicity, socioeconomic level or parental education. Sixty-two students (54.8%) were completely asymptomatic and the others had at least one gastrointestinal symptom. H. pylori infection was asymptomatic in 56.8% and symptomatic in 53.2% of students. There was no significant difference between infected and uninfected children with regard to body weight, height and body mass index.ConclusionThe prevalence of H. pylori infection is high among high-school students on Lanyu Island. There is no evidence that infection is related to growth failure

    Identifying the attack sources of botnets for a renewable energy management system by using a revised locust swarm optimisation scheme

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    Distributed denial of service (DDoS) attacks often use botnets to generate a high volume of packets and adopt controlled zombies for flooding a victim’s network over the Internet. Analysing the multiple sources of DDoS attacks typically involves reconstructing attack paths between the victim and attackers by using Internet protocol traceback (IPTBK) schemes. In general, traditional route-searching algorithms, such as particle swarm optimisation (PSO), have a high convergence speed for IPTBK, but easily fall into the local optima. This paper proposes an IPTBK analysis scheme for multimodal optimisation problems by applying a revised locust swarm optimisation (LSO) algorithm to the reconstructed attack path in order to identify the most probable attack paths. For evaluating the effectiveness of the DDoS control centres, networks with a topology size of 32 and 64 nodes were simulated using the ns-3 tool. The average accuracy of the LS-PSO algorithm reached 97.06 for the effects of dynamic traffic in two experimental networks (number of nodes = 32 and 64). Compared with traditional PSO algorithms, the revised LSO algorithm exhibited a superior searching performance in multimodal optimisation problems and increased the accuracy in traceability analysis for IPTBK problems
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