• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권6호
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• pp.1479-1495
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• 2012

Spectrum scarcity seems to be the most challenging issue to be solved in new wireless telecommunication services. It is shown that spectrum unavailability is mainly due to spectrum inefficient utilization and inappropriate physical layer execution rather than spectrum shortage. Daily increasing demand for new wireless services with higher data rate and QoS level makes the upgrade of the physical layer modulation techniques inevitable. Orthogonal Frequency Division Multiple Access (OFDMA) which utilizes multicarrier modulation to provide higher data rates with the capability of flexible resource allocation, although has widely been used in current wireless systems and standards, seems not to be the best candidate for cognitive radio systems. Filter Bank based Multi-Carrier (FBMC) is an evolutionary scheme with some advantages over the widely-used OFDM multicarrier technique. In this paper, we focus on the total throughput improvement of a cognitive radio network using FBMC modulation. Along with this modulation scheme, we propose a novel uplink radio resource allocation algorithm in which fairness issue is also considered. Moreover, the average throughput of the proposed FBMC based cognitive radio is compared to a conventional OFDM system in order to illustrate the efficiency of using FBMC in future cognitive radio systems. Simulation results show that in comparison with the state of the art two algorithms (namely, Shaat and Wang) our proposed algorithm achieves higher throughputs and a better fairness for cognitive radio applications.

• 한국화재소방학회논문지
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• 제24권2호
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• pp.9-20
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• 2010

본 연구는 아직 초보수준인 국내기업의 업무연속성 유지를 위한 재해경감 활동계획 수립 및 실행에 대한 방향을 제시하였으며, 조기대응체계 구축을 통하여 어떠한 재난에도 안전을 기할 수 있는 기업 연속성 유지 방안을 모색하였다. 이를 실현하기 위하여 국내 재난관리 표준으로 채택된 사고대비 및 업무연속성 관리의 가이드라인을 분석하였고, 국내기업에 쉽게 적용할 수 있는 실행지침을 제시하였으며, A기업을 대상으로 재해경감활동계획 수립 및 정보기술을 활용하는 방안을 연구하였다. 특히 사고대비 및 업무연속성 관리의 가이드라인 5단계 주요 절차 중 계획수립단계의 위험 평가, 영향분석, 예방경감계획 및 대응관리계획 수립에 대한 모델을 제시하였고, 국내 재해경감활동이 활성화되기 위한 방안을 도출하였으며, 재난대응 수준을 향상시키기 위하여 필요한 정보기술 부분도 제시하였다.

• 한국산업정보학회논문지
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• 제24권6호
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• pp.81-93
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• 2019

고객의 요구나 선호도가 다양해짐에 따라 제품의 다양화가 필요하지만, 이는 오퍼레이션스의 비효율성이 야기될 수 있어 기업의 중요 관심사가 되고 있다. 따라서 원활한 오퍼레이션스 기능 수행을 위해 기업들은 제품의 모듈화 구조를 도입해 왔다. 하지만 신제품 개발 과정에서 모듈화의 효과를 계량적으로 분석한 연구는 미흡하다. 이에 본 연구는 기존 제품에 신기술이 포함된 부품이 도입되는 제품개발의 상황에서 모듈화가 기업의 수익에 미치는 영향에 관한 계량모델을 개발하고 이를 분석하여 몇 가지 중요한 명제를 도출함으로써 신제품 개발 시 고려해야 할 신기술 도입 및 모듈화의 의사결정에 필요한 가이드라인을 제시하였다. 연구 결과, i) 제품의 업그레이드가 용이하거나, ii) 외부요인으로 인해 제품의 가격이 높게 책정되어야 할 경우, iii) 신기술 투자비용의 효과가 불확실할 경우, 모듈화 수준을 높이는 노력이 필요하고, 모듈화에 대한 수요탄력성이 낮은 제품의 신제품 개발 시에는 신기술 도입의 투자비용을 늘리는 것이 바람직하다.

• 한국인터넷방송통신학회논문지
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• 제9권3호
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• pp.217-224
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• 2009

기존의 교육용 소형 다관절로봇은 펌웨어를 이용하여 개발해왔다. 이런 시스템일 경우 단순동작만 수행할 수 있기 때문에 교육용으로 활용가치가 떨어진다. 그러나 교육용 소형 다관절로봇에 RTOS를 적용하면 다양한 동작의 수행이 가능하다. RTOS를 적용하면 시스템의 효율이 높아지지만 SW 복잡도가 높아져 교육용으로 사용하기 어려운 문제가 있다. 이런 문제를 해결하기 위해서 본 논문에서는 디자인 패턴과 리팩토링을 적용한다. 디자인 패턴과 리팩토링을 적용하여 RTOS를 설계하면 이미 알려진 패턴의 개념이 사용되기 때문에 RTOS의 전문 개발자가 아니어도 이해하기 쉬어진다. 뿐만 아니라 설계가 문서화되기 때문에 기존의 RTOS를 이용하여 새로운 시스템에 알맞은 RTOS로 변경이 용이해 진다. 그래서 본 논문에서는 디자인패턴을 사용하여 RTOS를 설계하고 RTOS 코드에 리팩토링을 적용하였다.

• 한국지진공학회논문집
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• 제20권7_spc호
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• pp.509-516
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• 2016

Secure operation of hospitals during and right after earthquake is essential. Past lessons from earthquake damages have shown that most of the injured and the death occurred within 30 minutes after earthquake and the portion of nonstructural damage has become significant. However, hospital buildings in Korea have not prepared fully to address such rising issues. This paper is to study what type of damage patterns are related to hospital buildings and how to develop a preparedness plan to keep hospitals operational at all earthquakes if possible. This paper first reviews on past earthquake damages reported as critical to hospital buildings while classifying them into four groups: (1) structural element; (2) architectural-nostructural element; (3) medical equipments and contents; and (4) utility facility. Upon such classification, some detailed concerns can be specified under each group explicitly. Then a hierarchy for hospital building is also developed for the classified groups, which enables us to identify required things for the enhancement of seismic performance of hospital building that consists of heterogeneous elements. To upgrade the level of seismic performance for existing hospital buildings, the concept of performance-based approach can be adopted to address the heterogeneous problems in a systematic and stepwise manner. Finally a conceptual framework for the seismic risk assessment for hospital building is proposed toward the seismic enhancement of hospital buildings using performance-based approach.

• 산업경영시스템학회지
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• 제43권3호
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• pp.21-28
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• 2020

Aftermarket refers to a market in which a company sells complementary goods, replacements of parts, and upgrade or maintenance services to consumers after selling them main durable goods. Intuitively, consumers who purchase main durable goods become major potential customers in subsequent aftermarket. Thus the existence of the aftermarket has a significant impact on pricing of the main durable goods as well as the aftermarket products. In this study, we analyze the effect of aftermarket on the pricing strategy for a company selling both main durable goods and aftermarket products. To do this we first divided the market into markets where the aftermarket products are indispensable and optional. Based on the proposed market types, the profit maximizing solutions are derived using two-period model, and the impacts of consumers' undervaluation of aftermarket product prices on pricing strategy are analyzed. The results can be summarized as follows : (1) Regardless of the market type, the total profits were found to be inversely proportional to the consumer's awareness accuracy of product prices in the aftermarket. This is in line with marketing efforts that sales companies have made intuitively to make consumers underestimate the cost of the aftermarket. (2) If aftermarket product is indispensable, only revenue from the aftermarket is sought. On the other hand, if aftermarket product is optional, revenue from the main durable good as well as the aftermarket product will be sought simultaneously. (3) Moreover, when aftermarket product is optional, the lower the awareness accuracy of consumers, the higher the price and profit of the main durable goods, while the lower the price and profit of the aftermarket products. This is contrary to the intuition that the lower the consumer's valuation of the costs of aftermarket, the more advantageous it would be to rely on aftermarket products rather than on main durable goods.

• 대한토목학회논문집
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• 제34권6호
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• pp.1901-1910
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• 2014

현재 국내외 BIM을 도입한 사회기반시설 적용 사례는 BIM 시각화를 기반으로 하는 설계 및 시공단계에 제한되며 효율적 운영을 위한 설계, 시공 정보 활용 방안에 대한 연구는 매우 미미하다. 본 연구는 최근 국내 경제 발전에 많은 기여를 하고 있는 산업설비군 중 운영 및 유지관리 능력 향상이 필요한 하수처리시설을 대상으로 BIM 기반 통합 유지관리 프로토타입 시스템을 개발하였다. 본 연구에 사용된 주요 연구 방법으로는 시스템 개발 순서에 따라 진행하였으며, 최종적으로 개발된 프로토타입 시스템의 현업 적용 가능성을 판단하기 위하여 4가지의 대표적 유지관리 시나리오를 제안하고 산출물을 통해서 문제 해결이 가능함을 보여준다. 최근 상하수도시설의 자산관리 개념 도입 노력과 유역기반 운영 및 유지관리의 정책 및 제도 적 변화, 그리고 국내 상하수도 기술력의 해외시장 진출 필요에 따른 운영 및 유지관리 능력 고도화를 위해 본 연구결과가 일조할 수 있기를 기대해 본다.

• Journal of Radiation Protection and Research
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• 제41권3호
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• pp.185-190
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• 2016

Background: In order to measure neutron energy spectra, the conventional Bonner Sphere Spectrometers (BSS) are widely used. In this spectrometer, several measurements with different size Bonner spheres are required. Operators should, therefore, place these spheres in several times to a measurement point where radiation dose might be relatively high. In order to reduce this effort, novel neutron energy spectrometer using an onion-like single Bonner sphere was proposed in our group. This Bonner sphere has multiple sensitive spherical shell layers in the single sphere. In this spectrometer, a band-shaped thermal neutron detection medium, which consists of a LiF-ZnS mixed powder scintillator sheet and a wavelength-shifting (WLS) fiber readout, was looped to each sphere at equal angular intervals. Amount of LiF neutron converter is reduced near polar region, where the band-shaped detectors are concentrated, in order to uniform the directional sensitivity. The LiF-ZnS mixed powder has an advantage of extremely high light yield. However, since it is opaque, scintillation photons cannot be collect uniformly. This type of detector shows no characteristic shape in the pulse height spectrum. Subsequently, it is difficult to set the pulse height discrimination level. This issue causes sensitivity fluctuation due to gain instability of photodetectors and/or electric modules. Materials and Methods: In order to solve this problem, we propose to replace the LiF-ZnS mixed powder into a flexible and Transparent RUbber SheeT type $LiCaAlF_6$ (TRUST LiCAF) scintillator. TRUST LiCAF scintillator can show a peak shape corresponding to neutron absorption events in the pulse height spectrum. Results and Discussion: We fabricated the prototype detector with five sensitive layers using TRUST LiCAF scintillator and conducted basic experiments to evaluate the directional uniformity of the sensitivity. Conclusion: The fabricated detector shows excellent directional uniformity of the neutron sensitivity.

• 한국간호교육학회지
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• 제10권1호
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• pp.20-32
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• 2004

Purpose: The purpose of this study is to investigate undergraduate nursing students' volunteering activities, volunteering motivation- needs, sociability and satisfaction in their major for those who take the social service activities, and to provide basic information for operating the credit system of social service activity as service-learning system. Method: This study is a descriptive study and the participants were 363 of 2nd- and 3rd-year students at a nurses' college in I City, who completed the basic course of volunteering, and the survey was conducted during April 2004. Result: The group who participated in counseling service as a volunteering activity was high in volunteering motivation-needs, sociability and satisfaction in their major. In the group who performed volunteering through circle activities, those who volunteered for children, who participated longer and who had an active attitude showed high volunteering motivation-needs. In the group who had volunteering activities during weekdays, those who took an active attitude toward volunteering showed high sociability. Those who were somewhat dissatisfied with volunteering activities, however, showed significantly high sociability. Satisfaction in the major, namely, nursing was higher in senior students, in those who participated in volunteering activities for the first time at college, those who had religion, those who are active in volunteering activities and those who were highly satisfied with volunteering activities. Considering that active attitude toward volunteering activities and high volunteering motivation-needs enhance nursing students' satisfaction in their major, it is necessary to upgrade the current volunteering activities to the level of service learning. That is, it is necessary to develop new service learning in nursing curriculum that utilizes volunteering activities as well as what they learn in major for community societies.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2008년도 춘계학술발표대회 논문집
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• pp.116-122
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• 2008

As a model house has attempted a role change from a conceptual perspective as a housing cultural center starting from the 90ties, it began to direct the change into a high end building. In particular, large construction companies have recently invested on an unimagined scale, unlike in the past, in building a model house and pursued the construction of new attractions of cities as well as the upgrade of a brand image by hiring and implementing the designs of celebrity architects or designers. In addition, they have been in pursuit of a change by enhancing the satisfaction and pride of residents by offering spaces and programs for various cultural arts for apartment residents or potential customers and having them participate in those programs. This study aims to expound on the possibility of the utilization of a housing cultural center as a local complex community center by analyzing the spatial organization and the operational program of a housing cultural center appearing since the 90ties. With this aim, the study analyzed the cases of a complex community center and the program and the operational method of a housing cultural center within the case study in order to propose the possibilities for the utilization of a local complex community center. The elevation of the cultural and economic level of citizens and a rapid social change are shown as various demands for welfare, and the subsequent social physical change has led to the expansion of a space as a complex community. A housing cultural center is also directed to grow as a complex community center from the perspective of diverse demands and participations of consumers, and prepares a field for a broad spectrum of communications from the perspective of housing and cities.