• Title/Summary/Keyword: reduction strategies

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A PRACTICAL LOOK AT MONTE CARLO VARIANCE REDUCTION METHODS IN RADIATION SHIELDING

  • Olsher Richard H.
    • Nuclear Engineering and Technology
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    • v.38 no.3
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    • pp.225-230
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    • 2006
  • With the advent of inexpensive computing power over the past two decades, applications of Monte Carlo radiation transport techniques have proliferated dramatically. At Los Alamos, the Monte Carlo codes MCNP5 and MCNPX are used routinely on personal computer platforms for radiation shielding analysis and dosimetry calculations. These codes feature a rich palette of variance reduction (VR) techniques. The motivation of VR is to exchange user efficiency for computational efficiency. It has been said that a few hours of user time often reduces computational time by several orders of magnitude. Unfortunately, user time can stretch into the many hours as most VR techniques require significant user experience and intervention for proper optimization. It is the purpose of this paper to outline VR strategies, tested in practice, optimized for several common radiation shielding tasks, with the hope of reducing user setup time for similar problems. A strategy is defined in this context to mean a collection of MCNP radiation transport physics options and VR techniques that work synergistically to optimize a particular shielding task. Examples are offered in the areas of source definition, skyshine, streaming, and transmission.

Meeting the Energy Reduction Goal on a High Rise Building thru IPD Framework

  • Jeong, Pyung Oh;Lee, Peter;Kim, Sang-jin
    • International Journal of High-Rise Buildings
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    • v.2 no.2
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    • pp.93-96
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    • 2013
  • Greenhouse gas emissions and excessive energy consumption have been an on-going world issue nowadays. We can find that the majority portion is caused by high-rise office buildings. In order to resolve these problems, it is extremely important to implement various active or passive strategies in a building design. To successfully meet these design goals and energy reduction approaches, a project building must utilize an efficient design process from the early start. One of the most effective project delivery process called Integrated Project Delivery (IPD) will be implemented in a case study project building (KEPCO) during design phase and show how important it is to plan a project's green environmental performance goal together through an early collaboration from all key project participants, which helps to construct an successful green building design without any critical construction pitfalls.

Recent strategies for improving the quality of meat products

  • Seonmin Lee;Kyung Jo;Seul-Ki-Chan Jeong;Hayeon Jeon;Yun-Sang Choi;Samooel Jung
    • Journal of Animal Science and Technology
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    • v.65 no.5
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    • pp.895-911
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    • 2023
  • Processed meat products play a vital role in our daily dietary intake due to their rich protein content and the inherent convenience they offer. However, they often contain synthetic additives and ingredients that may pose health risks when taken excessively. This review explores strategies to improve meat product quality, focusing on three key approaches: substituting synthetic additives, reducing the ingredients potentially harmful when overconsumed like salt and animal fat, and boosting nutritional value. To replace synthetic additives, natural sources like celery and beet powders, as well as atmospheric cold plasma treatment, have been considered. However, for phosphates, the use of organic alternatives is limited due to the low phosphate content in natural substances. Thus, dietary fiber has been used to replicate phosphate functions by enhancing water retention and emulsion stability in meat products. Reducing the excessive salt and animal fat has garnered attention. Plant polysaccharides interact with water, fat, and proteins, improving gel formation and water retention, and enabling the development of low-salt and low-fat products. Replacing saturated fats with vegetable oils is also an option, but it requires techniques like Pickering emulsion or encapsulation to maintain product quality. These strategies aim to reduce or replace synthetic additives and ingredients that can potentially harm health. Dietary fiber offers numerous health benefits, including gut health improvement, calorie reduction, and blood glucose and lipid level regulation. Natural plant extracts not only enhance oxidative stability but also reduce potential carcinogens as antioxidants. Controlling protein and lipid bioavailability is also considered, especially for specific consumer groups like infants, the elderly, and individuals engaged in physical training with dietary management. Future research should explore the full potential of dietary fiber, encompassing synthetic additive substitution, salt and animal fat reduction, and nutritional enhancement. Additionally, optimal sources and dosages of polysaccharides should be determined, considering their distinct properties in interactions with water, proteins, and fats. This holistic approach holds promise for improving meat product quality with minimal processing.

Personal Management Strategies for the Financial Improvement of Seoul Metropolitan Subway Corporation (서울시지하철공사 경영혁신을 위한 인력운영 개선방안)

  • 황기연;백성준
    • Proceedings of the KSR Conference
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    • 1998.05a
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    • pp.172-183
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    • 1998
  • The purpose of this study is to reduce the number of employees hired by Seoul Metropolitan Subway Corporation(SMSC) as a way of responding to deteriorating financial deficit problem. For the reduction, the personnel structure of Seoul Metro Rapid Transit Subway(SMRTS) newly founded in 1995 is benchmarked. Several assumptions are set for seeking the persuasive alternative; 1) no compulsory reduction of existing personnel, 2) raising the salary of SMSC to the same level of SMRTS for compensating intensified work burden, 3) hiring new employees to the amount of one-third of the reduced workforce for minimizing the problems associated with the reduction. The study suggests that the personnel reduction in relevant parts be planned in the following ways; 1) passenger transport part: from daily 3 shifts of 4 group to 2 shifts of 3 group, 2) fleet inspection, civil d: electric engineering, railtrack maintenance, signal parts: from 12 day-off to 10day-off, 3) architecture, AFC parts: from 2 shifts of 3 group to daily work, 4) fleet maintenance, architecture parts: expanding out-sourcing & automation, and 5) headquarter part: 10% reduction of the total of office workers. The study finds, by implementing the plan, that 1,270 employee can be reduced, and that aggregate 106.8 billion won will be saved for the next 10 years.

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Perspectives on Solar Energy Development in the Age of Climate Change Convention (기후변화협약 시대의 태양에너지 개발 전망)

  • Hong, Wuk-Hee
    • Solar Energy
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    • v.18 no.1
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    • pp.3-18
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    • 1998
  • Since entered into force in 1994, United Nations Framework Convention on Climate Change(UNFCCC) would require all the member nations to adopt national programme for mitigating climate change and industrialized countries to undertake specific commitments of carbon dioxide emission reduction. Considering all the situation, it may be safe to assume that Korea would undertake such commitment early in the next century. Unfortunately, however, we are in the position that is very disadvantageous in preparing national strategies for carbon dioxide reduction mainly due to our rigid energy-intensive economic structure and poor geographic conditions. Solar energy is regarded as most available renewable energy resource in Korea and hence development of solar energy technology would serve as one of most effective alternatives for energy conservation and renewable energy utilization. In this regard, the presenting paper discuss the perspectives on solar energy development in relation to carbon dioxide reduction strategies. Such technologies of solar cell mass production and solar heating were considered to be most advantageous among many solar energy solutions discussed in this paper.

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A Review of Strategies to Improve the Stability of Carbon-supported PtNi Octahedral for Cathode Electrocatalysts in Polymer Electrolyte Membrane Fuel Cells

  • In Gyeom Kim;Sung Jong Yoo;Jin Young Kim;Hyun S. Park;So Young Lee;Bora Seo;Kwan-Young Lee;Jong Hyun Jang;Hee-Young Park
    • Journal of Electrochemical Science and Technology
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    • v.15 no.1
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    • pp.96-110
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    • 2024
  • Polymer electrolyte membrane fuel cells (PEMFCs) are green energy conversion devices, for which commercial markets have been established, owing to their application in fuel cell vehicles (FCVs). Development of cathode electrocatalysts, replacing commercial Pt/C, plays a crucial role in factors such as cost reduction, high performance, and durability in FCVs. PtNi octahedral catalysts are promising for oxygen reduction reactions owing to their significantly higher mass activity (10-15 times) than that of Pt/C; however, their application in membrane electrode assemblies (MEAs) is challenged by their low stability. To overcome this durability issue, various approaches, such as third-metal doping, composition control, halide treatment, formation of a Pt layer, annealing treatment, and size control, have been explored and have shown promising improvements in stability in rotating disk electrode (RDE) testing. In this review, we aimed to compare the features of each strategy in terms of enhancing stability by introducing a stability improvement factor for a direct and reasonable comparison. The limitations of each strategy for enhancing stability of PtNi octahedral are also described. This review can serve as a valuable guide for the development of strategies to enhance the durability of octahedral PtNi.

The Effects of Conflict Resolution Group Counseling on Conflict Resolution Strategy and Friendship Quality of Children (갈등해결 집단상담이 아동의 갈등해결전략과 친구관계의 질에 미치는 영향)

  • Song, Ju-Youn;Eun, Hyuk-Gi
    • The Korean Journal of Elementary Counseling
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    • v.8 no.1
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    • pp.123-139
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    • 2009
  • The purpose of this study was to verify the effects of a conflict resolution program on conflict resolution strategies and friendship quality of children. The subjects of this study were higher-grader students of elementary school. Out of the students, 18 were into the experimental group, while the rest were into the control-group. The experimental design was the pretest-posttest control group design, and the 50-minutes conflict resolution program was treated for the experimental group twice per week (a total of 11 sessions). The scale of conflict resolution strategies presented by Ha Ji Wean (2005) and the scale of friendship quality of children presented by Rhee Un Hai and Koh Yun Joo (1999) were used as the measurement tools in this study. In order to supply the limitations of quantitative data, the journals of group participation of each session and the participation reports after the completion of the program were qualitatively analyzed. The results of hypotheses verification were as follows; First, conflict resolution strategies conflict was significant difference in enhancement of the compromising-integrating strategy and the obliging strategy, and reduction of the dominating strategy. Second, friendship quality was significant difference in enhancement of the friendship positive function, and friendship satisfaction, and in reduction of the friendship negative aspect, The results of the study confirmed that the conflict resolution program affected both conflict resolution strategies and the friendship quality of children.

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A Study on the Reduction Measures of CO2 Emission in the Commercial Sector of Korea (상업부분에 있어서 이산화탄소 저감방안에 관한 연구)

  • Lee, Dong Kun;Jung, Tae Yong;Youn, So Won
    • Journal of Environmental Impact Assessment
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    • v.8 no.4
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    • pp.59-72
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    • 1999
  • The purpose of the study is to propose the concrete and realistic alternative measures for $CO_2$ emission reduction on commercial sector. To achieve the purpose, this study adopted AIM/KOREA simulation model modified from AIM(Asia-Pacific Integrated Model) originally developed by Japan National Environmental Research Institute. The results of simulation demonstrate that the $CO_2$ emission from the commercial sector in 1995 was estimated 864 million TC(tons of carbon); however, according to the base scenario, $CO_2$ emission in 2020 is expected to be increased to 1,872 million TC, which is 2.17 times greater than that in 1995. In order to mitigate the ever-increasing $CO_2$ emission, the results of AIM/KOREA simulations under various scenarios showed that the 30-thousand-won carbon tax scenario does not successfully motivate the selection of advanced technology; however, with the 300-thousand-won carbon tax, a substantial amount of $CO_2$ emission reduction by 1.69 million TC from the BaU((Business-as-Usual)scenario is expected to be achieved by year 2020. Such substantial reduction of $CO_2$ emission under the 300-thoudsand-won carbon tax scenario is due to the introduction of advanced technology, such as use of condensing boilers, forced by heavier carbon tax. Under the scenario that presumes the maximum introduction of gas-burning industrial appliances, an 2.66 million TC of $CO_2$ reduction was expected. The results of this study suggest that the $CO_2$ emission reduction measures can be interpreted in many different views. However, if people and industries are fully aware of the economic benefit of energy saving, a certain level of $CO_2$ reduction by a successful introduction of advanced energy saving technology appears to be achieved without carbon tax or subsidies.

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Airborne infection risk of respiratory infectious diseases and effectiveness of using filter-embeded mechanical ventilator and infectious source reduction device such as air cleaner (실내 공간에서의 호흡기 감염병 공기전파감염 위험도와 공기정화장치(필터 임배디드 기계식 환기설비 및 공기청정기 등 실내 감염원 저감 장치) 사용에 따른 효율)

  • Park, Sungjae;Park, Geunyoung;Park, Dae Hoon;Koo, Hyunbon;Hwang, Jungho
    • Particle and aerosol research
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    • v.16 no.4
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    • pp.73-94
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    • 2020
  • Particulate infectious sources, including infectious viruses, can float in the air, causing airborne infections. To prevent indoor airborne infection, dilution control by ventilation and indoor air cleaners are frequently used. In this study, the risk of airborne infection by the operation of these two techniques was evaluated. In case of dilution control by ventilation, a high efficiency air filter was embedded at the inlet of supply air. In this study, infectious source reduction devices such as indoor air cleaner include all kinds of mechanical-filters, UV-photo catalysts and air ionizers through which air flow is forced by fans. Two mathematical models for influenza virus were applied in an infant care room where infants and young children are active, and the risk reduction efficiency was compared. As a result, in the case of individually operating the ventilator or the infectious source reduction device, the airborne infection risk reduction efficiencies were 55.2~61.2% and 53.8~59.9%, respectively. When both facilities were operated, it was found that the risk of airborne infection was reduced about 72.2~76.8%. Therefore, simultaneous operation of ventilation equipment and infectious source reduction device is the most effective method for safe environment that minimizes the risk of airborne infection of respiratory infectious diseases. In the case of a space where sufficient ventilation operation is difficult, it was found that the operation of an infectious source reduction device is important to prevent the spread of infectious diseases. This study is meaningful in that it provides an academic basis for strategies for preventing airborne infection of respiratory infectious diseases.

An Enhancement of Japanese Acoustic Model using Korean Speech Database (한국어 음성데이터를 이용한 일본어 음향모델 성능 개선)

  • Lee, Minkyu;Kim, Sanghun
    • The Journal of the Acoustical Society of Korea
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    • v.32 no.5
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    • pp.438-445
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    • 2013
  • In this paper, we propose an enhancement of Japanese acoustic model which is trained with Korean speech database by using several combination strategies. We describe the strategies for training more than two language combination, which are Cross-Language Transfer, Cross-Language Adaptation, and Data Pooling Approach. We simulated those strategies and found a proper method for our current Japanese database. Existing combination strategies are generally verified for under-resourced Language environments, but when the speech database is not fully under-resourced, those strategies have been confirmed inappropriate. We made tyied-list with only object-language on Data Pooling Approach training process. As the result, we found the ERR of the acoustic model to be 12.8 %.