• Title/Summary/Keyword: Capacity utilization

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Coordinating Production Order and Scheduling Policy under Capacity Imbalance

  • Rhee, Seung-Kyu
    • Journal of the Korean Operations Research and Management Science Society
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    • v.21 no.2
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    • pp.171-186
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    • 1996
  • This paper comes from an observation that overemphasis on capacity utilization meausre, which is usual under capacity shortage, can seriously hurt the firm's profit and potential process improvement. We suggest a model that can be used in designing a coordination scheme for decentralized marketing and manufacturing activities. Using a price and time-sensitive demand and capacitated lotsizing model, we derive an effective communication medium betwen marketing and manufacturing. This Balance Indicator of process capacity and flexibility also implies that the increase in capacity availability and setup time reduction should be balanced by its market requirements. This is particularly important when a firm tries to improve its process capability by kaizen. Further, the model can be used to show the comparative performances of scheduling policies under capacity imbalnce. We show the shortening the scheduling cycle can improve the firm profit without changing the simple scheduling rule.

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Evaluation of the Nutritional Composition and Quality Traits of Rabbit Meat (토끼고기의 영양성분 및 품질특성 평가)

  • Lee, Jeong Ah;Jung, Suk Han;Seol, Kuk-Hwan;Kim, Hyoun-Wook;Cho, Soohyun;Kang, Sun Moon
    • Journal of the Korean Society of Food Culture
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    • v.37 no.2
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    • pp.171-177
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    • 2022
  • This study evaluated the nutritional composition and quality traits of rabbit meat as compared to chicken meat. Samples of loin (M. longissimus dorsi) and breast meats were collected from rabbit and chicken carcasses, respectively. The meats were then analyzed for the proximate composition, collagen and energy contents, fatty acid composition, myoglobin and heme iron contents, pH value, water-holding capacity (WHC), cooking loss, meat color, Warner-Bratzler shear force (WBSF) value, and texture profile. Compared to chicken breast meat, lower (p<0.05) protein content and higher (p<0.05) ash and collagen contents were obtained in rabbit loin meat. Rabbit meat remarkably had higher (p<0.05) total polyunsaturated fatty acids (PUFA) and linolenic acid contents and lower (p<0.05) n-6/n-3 PUFA ratio as compared to chicken meat. The pH value and WHC were lower (p<0.05) in rabbit meat than in chicken meat (p<0.05). Rabbit meat exhibited lower (p<0.05) L* value and higher (p<0.05) a* and b* values compared to chicken meat (p<0.05). The WBSF value, hardness, and gumminess were higher (p<0.05) in rabbit meat than in chicken meat (p<0.05). These findings suggest that rabbit meat has higher essential n-3 PUFA, darker color, and firmer texture as compared to chicken meat.

Ionic Additives to Increase Electrochemical Utilization of Sulfur Cathode for Li-S Batteries

  • Seong, Min Ji;Yim, Taeeun
    • Journal of Electrochemical Science and Technology
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    • v.12 no.2
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    • pp.279-284
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    • 2021
  • The high theoretical specific capacity of lithium-sulfur (Li-S) batteries makes them a more promising energy storage system than conventional lithium-ion batteries (LIBs). However, the slow kinetics of the electrochemical conversion reaction seriously hinders the utilization of Li-S as an active battery material and has prevented the successful application of Li-S cells. Therefore, exploration of alternatives that can overcome the sluggish electrochemical reaction is necessary to increase the performance of Li-S batteries. In this work, an ionic liquid (IL) is proposed as a functional additive to promote the electrochemical reactivity of the Li-S cell. The sluggish electrochemical reaction is mainly caused by precipitation of low-order polysulfide (l-PS) onto the positive electrode, so the IL is adopted as a solubilizer to remove the precipitated l-PS from the positive electrode to promote additional electron transfer reactions. The ILs effectively dissolve l-PS and greatly improve the electrochemical performance by allowing greater utilization of l-PS, which results in a higher initial specific capacity, together with a moderate retention rate. The results presented here confirmed that the use of an IL as an additive is quite effective at enhancing the overall performance of the Li-S cell and this understanding will enable the construction of highly efficient Li-S batteries.

Extension Specialist's Role and Capacity of Knowledge Management (지식경영을 위한 농촌지도요원의 역할과 역량)

  • Jolh, Rok-Hwan
    • Journal of Agricultural Extension & Community Development
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    • v.13 no.2
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    • pp.385-400
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    • 2006
  • The study aims to explore the rural extension specialist's role and capacity of knowledge management (KM) extension service in the knowledge based society. According to major findings through previous study and literature review, the followings were concluded. Rural extension educator's role and ability of knowledge management composed four processes by the stage of knowledge process: knowledge creation-knowledge storage-knowledge utilization-knowledge share. As a adoption of the knowledge management in rural extension service, at the knowledge creation the rural extension educator's role of KM are four roles which needed fourteen abilities to carry out them successfully. For at the knowledge storage the rural extension educator's role of KM are eight roles which needed eight abilities to carry out them successfully. For at the knowledge utilization the rural extension educator's role of KM are eight roles which needed ten abilities to carry out them successfully. Lastly for at the knowledge sharing the rural extension educator's role of KM are nine roles which needed 8 abilities to carry out them successfully.

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A Study on the Utilization of Waste Foundry Sand as Backfill Material for Underground Electric Utility Systems (방식사의 지하 전력시설용 되메움재 활용에 관한 연구)

  • 이대수;홍성연;김경열
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.665-672
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    • 2002
  • In this paper, the utilization of waste foundry sand produced in the molding process is studied as a backfill material for underground electric utility systems such as concrete box structures and pipe lines for power supply. The physical, chemical and thermal properties for waste foundry sand are investigated for mechanical stability, environmental hazard and power transmission capacity. Also its properties are compared with the natural river sand. The test results show that waste foundry sand can be utilized for underground concrete box structures as a backfill material; however, it can not be applied to underground pipe lines due to high thermal resistivity or low power transmission capacity.

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Digital Current Controller with Smith-Predictor for PWM Converters

  • Lee, Jin-Woo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.1 no.1
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    • pp.7-11
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    • 1996
  • From the cost-effective point of view, it is very important to design a current with the highest utilization factor of current capacity of power devices. This can be accomplished by a current controller without overshoot irrespective of the varying bounds of control voltage in PWM converters and the dead time due to the time delay. This paper suggests a novel decoupled controller with Smith-Predictor which has the fast control response without overshoot and steady stats error and also deal with the design method of the controller for PWM converters. The extensive digital simulations done by SIMULINK/MATLAB show that the suggested controller guarantees the full utilization of current capacity of power devices and the decoupled current control behavior.

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Fluctuation in operational energy efficiency of ships and its implications for performance appraisal

  • Zhang, Shuang;Yuan, Haichao;Sun, Deping
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.13 no.1
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    • pp.367-378
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    • 2021
  • This paper develops a dynamic regression model to quantify the contribution of key external factors to operational energy efficiency of ships. On this basis, kernel density estimation is applied to explore distribution patterns of fluctuations in operational performance. An empirical analysis based on these methods show that distribution of fluctuations in Energy Efficiency Operational Indicator (EEOI) is leptokurtic and fat tailed, rather than a normal one. Around 85% of fluctuations in EEOI can be jointly explained by capacity utilization and sailing speed, while the rest depend on other external factors largely beyond control. The variations in capacity utilization and sailing speed cannot be fully passed on to the energy efficiency performance of ships, due to complex interactions between various external factors. The application of the methods is demonstrated, showing a potential approach to develop a rating mechanism for use in the legally binding framework on operational energy efficiency of ships.

Measurement of Fishing Capacity of Offshore Fisheries in Korea (우리나라 근해어업의 어획능력 측정에 관한 연구)

  • Kim Do-Hoon
    • The Journal of Fisheries Business Administration
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    • v.37 no.1 s.70
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    • pp.1-24
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    • 2006
  • Reducing fishing capacity is one of current issues in the international fisheries. This is because that increased fishing capacity has caused not only fish stocks to be depleted, but also additional fishing costs to be incurred, which resulted in reduction of economically viability of fisheries. For this reason, FAO adopted the International Plan of Action for the Management of Fishing Capacity' in 1999 and recommended member countries to estimate fishing capacity and to implement the policy to reduce fishing capacity. This study is aimed to measure fishing capacity of the Large Purse Seines Fishery that is one of offshore fisheries in Korea using both Peak - to - Peak Analysis and Data Envelopment Analysis in order to provide a policy information for preparation of domestic plan of action for the management of fishing capacity. The results of PTP Analysis were almost similar to those of DEA Analysis. The DEA results showed that the capacity utilization in 2004 was about 75%, it was obvious the capacity did not utilize enough. The sensitivity analysis on DEA results indicated that 24% of the number of ships, 26% of the tonnages, or 29% of the horse powers should be reduced if the present catch remained. In addition, if the catch remains at the MSY base level of large purse seines, the analysis suggested that the number of ships, tonnages and horse powers should be reduced by 15%, 18%, and 21% respectively.

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RETScreen(R) Ground Source Heat Pump(GSHP) Application for Korea (RETScreen(R) 지중열 히트펌프 모듈 한국 적용에 관한 연구)

  • Naveed Ahmed T;Park Sanghyun;Lee Euijoon;Kim Byungseon
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.678-683
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    • 2005
  • Korea is utilizing geothermal resources mainly in the bathing and swimming facilities with very few applications for industrial processes or space heating. It is estimated that geothermal capacity and annual utilization are 36.2MWt and 761TJ/year as compared to global capacity and annual utilization of 15,145MWt and 190,699 TJ/year. RETScreen software is a user's friendly tool for analyzing the technical and financial pre-feasibility of potential Renewable Energy (RE) projects that promotes the use of RE applications through the capacity building of planners, decision-makers and industries for successful implementation of RE projects. Strong ties between Canada and Korean organizations such as Korean Solar Energy Society (KSES) and the Korea Institute of Energy Research (KIER) exist for knowledge transfer about RETScreen. In this paper, an overview of RETScreen and its ground source heat pump (GSHP) model with a practical example of an existing project of a community hall in Canada are described to illustrate effectiveness of RETScreenin the implementation of RE technologies. The same community hall project is then evaluated hypothetically considering its location at Kangnyng, Korea. The main objective is to demonstrate how RETScreen GSHP model can also be utilized effectively for GSHP applications in Korea.

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Performance Analysis of Coordinated Cognitive Radio Networks under Fixed-Rate Traffic with Hard Delay Constraints

  • Castellanos-Lopez, S. Lirio;Cruz-Perez, Felipe A.;Rivero-Angeles, Mario E.;Hernandez-Valdez, Genaro
    • Journal of Communications and Networks
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    • v.16 no.2
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    • pp.130-139
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    • 2014
  • Due to the unpredictable nature of channel availability, carrying delay-sensitive traffic in cognitive radio networks (CRNs) is very challenging. Spectrum leasing of radio resources has been proposed in the so called coordinated CRNs to improve the quality of service (QoS) experienced by secondary users (SUs). In this paper, the performance of coordinated CRNs under fixed-rate with hard-delay-constraints traffic is analyzed. For the adequate and fair performance comparison, call admission control strategies with fractional channel reservation to prioritize ongoing secondary calls over new ones are considered. Maximum Erlang capacity is obtained by optimizing the number of reserved channels. Numerical results reveal that system performance strongly depends on the value of the mean secondary service time relative to the mean primary service time. Additionally, numerical results show that, in CRNs without spectrum leasing, there exists a critical utilization factor of the primary resources from which it is not longer possible to guarantee the required QoS of SUs and, therefore, services with hard delay constraints cannot be even supported in CRNs. Thus, spectrum leasing can be essential for CRN operators to provide the QoS demanded by fixed-rate applications with hard delay constraints. Finally, the cost per capacity Erlang as function of both the utilization factor of the primary resources and the maximum allowed number of simultaneously rented channels is evaluated.