• 한국통신학회논문지
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• 제34권2A호
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• pp.124-131
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• 2009

Cognitive radio has been proposed to mitigate the spectrum scarcity problem by allowing the secondary users to access the under-utilized frequency bands and opportunistically transmit. Spectrum sensing, as a key technology in cognitive radio, is required to reliably detect the presence of primary users to avoid the harmful interference. However, it would be very hard to reliably detect the presence of primary users due to the channel fading, shadowing. In this paper, we proposed a distributed cooperative spectrum sensing scheme based on conventional DF (decode-and-forward) cooperative diversity protocol. We fist consider the cooperation between two secondary users to illustrate that cooperation among secondary users can obviously increase the detection performance. We then compare the performance of DF based scheme with another conventional AF (amplify-and-forward) protocol based scheme. And it is found that the proposed scheme based on DF has a better detection performance than the one based on AF. After that, we extend the number of cooperative secondary users, and demonstrate that increasing the cooperation number can significantly improve the detection performance.

• 자동차안전학회지
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• 제14권2호
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• pp.26-38
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• 2022

This paper proposes multiple RLS and actuator performance index-based adaptive actuator fault-tolerant control and detection algorithms for longitudinal autonomous driving. The proposed algorithm computes the desired acceleration using feedback law for longitudinal autonomous driving. When actuator fault or performance degradation exists, it is designed that the desired acceleration is adjusted with the calculated feedback gains based on multiple RLS and gradient descent method for fault-tolerant control. In order to define the performance index, the error between the desired and actual accelerations is used. The window-based weighted error standard deviation is computed with the design parameters. Fault level decision algorithm that can represent three fault levels such as normal, warning, emergency levels is proposed in this study. Performance evaluation under various driving scenarios with actuator fault was conducted based on co-simulation of Matlab/Simulink and commercial software (CarMaker).

• 유통과학연구
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• 제13권3호
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• pp.61-67
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• 2015

Purpose - Exports have long been regarded as significant drivers of sustainable competitive advantage and growth among small and medium enterprises (SMEs). The export activities of SMEs are particularly important in the context of export-oriented economies such as Korea. Although many studies have examined the determinants of exports, it is difficult to find empirical studies about the determinants of the export performance of regional SMEs. This study investigates the determinants of export performance in the regional SME context based on an integrated approach that combines the environment factor of industrial organization theory, competitive strategy theory, and the competences of the resource-based view. Research design, data, and methodology - To empirically analyze the determinants of export performance in the regional SMEs, data were collected from firms in the Daegu metropolitan area. Data were collected directly through questionnaire surveys; in addition, secondary financial data were also taken from the KIS-VALUE database. Out of the 175 responses that were received, 143 were considered to be worth examining. After testing the reliability and validity of the variables through multiple items such as environmental turbulence and competitive strategy, hypotheses were verified by using five multi-regression models. These models were: a control model with organizational size and age, an environmental model with technology and market turbulence, a competency model with R&D and foreign distribution channels, a strategy model with product and market differentiation, and an integrated model including all of these variables. Results - First, as a control variable, the organization size has significant positive effects on export performance. Second, technology turbulence based on industrial organization theory has significant positive effects on export performance, but market turbulence does not affect export performance. Third, the foreign market distribution competency of the resource-based view has strong positive effects on export performance, but the R&D competency does not affect export performance. Fourth, the product differentiation strategy from competitive strategy theory positively impacts export performance, but market differentiation does not affect export performance. Finally, in the integrated model, only the foreign distribution competency of the resource-based view has a significant effect on export performance. Conclusions - The empirical results of this study verified the usefulness of the rationales behind the three theories to explain the export performance of the regional SMEs, especially the importance of the foreign market distribution competency from the resource-based view. With regard to practical considerations, this study's implications suggest that the use of technological environmental changes by industries is better than the use of market changes. Further, the use of the product differentiation strategy is more effective than the use of the market-driving strategy, and the distribution channel competency plays a stronger role than the technology-oriented competency with regard to the export performance position of regional SMEs. Future studies should examine relational perspectives, such as trust among channel partners. Therefore, the configuration approach is more useful in enhancing pragmatism by comparing high- and low-export companies.

• 한국도로학회논문집
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• 제19권6호
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• pp.165-173
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• 2017

PURPOSES : The current practice in car headlight visibility performance evaluation is based on the luminous intensity and illuminance of headlight. Such practice can be inappropriate from a visibility point of view where visibility indicates abilities to perceive an object ahead on the road. This study aimed at evaluating the appropriateness of current headlight evaluation method. METHODS : This study measured the luminance of object and road surface at unlit roadways. The variables were measured by vehicle type and by headlight lamp type. Based on the measurements, the distance where drivers can perceive an object ahead was calculated and then compared against such distance obtained by conventional visibility performance evaluation. RESULTS : The evaluation method based on illuminance of headlight is not appropriate when viewed from the visibility concept that is based on object-perceivable distance. Further, the results indicated a shorter object-perceiving distance even when road surface luminance is higher, thereby suggesting that illuminance of headlight and luminance of road surface are not the representative indices of nighttime visibility. CONCLUSIONS : Considering that this study utilized limited vehicle types and that road surface (background) luminance can vary depending on the characteristics of the given road surface, it would likely go too far to argue that this study's visibility performance evaluation results can get generalized to other conditions. Regardless, there is little doubt that the current performance evaluation criterion which is based on illuminance, is unreasonable. There should be future endeavors on the current subject which will need to explore study conditions further, under which more experiments should be conducted and effective methodologies developed for evaluating automotive headlight visibility performance. Needs are recognized particularly in the development of headlight visibility performance evaluation methodology which will take into account road surface (background) luminance and luminance contrast from various perspectives as the former indicates the driver's perception of the front road alignment and the latter being indicative of object perception performance.

• 산업경영시스템학회지
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• 제41권3호
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• pp.30-40
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• 2018

The purpose of this study is to examine the effect of project-based organizational resources on the business performance in the resource-based view (RBV) and dynamic capability one and analyze their relationship through an integrated model. The RBV argues that firms get competitive advantages when they have VRIN characterized resources but dynamic capability view argues that RBV has its limitation under volatility so it enables them to obtain competitive advantages in ever changing environments. This study analyzes data collected from 270 survey questionnaires on the project management related staff at the project-based organization among major companies in Korea. The result demonstrates that two project organizational resources on strategic and executional management with VRIN characteristics are found to bring positive effects on the organizational dynamic capabilities and also the dynamic capabilities such as integration & reconfiguration, organizational learning are verified to bring meaningful positive effects on the business performance. On the other hand, unlike previous studies, ambidexterity has quite a weak effect on the business performance. Therefore, we expect that the resources of the project-based organization with VRIN lead to strengthen the firm's business performance through organizational dynamic capabilities and produce high performance through the integrated model of RBV and dynamic capability one. The study has academic meanings that widely confirm the effects and characteristics of main elements of VRIN project organizational resources on the business performance of competitive advantage through the dynamic capabilities of the organization by the regression on the precedent studies regarding the project management resources and their relationship with the VRIO characteristics. The practical implication is that it is preferentially necessary for the organization to obtain VRIN resources and organizational dynamic capabilities, especially organizational learning to have sustainable competitive advantages.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제11권1호
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• pp.9-22
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• 2022

VR(Virtual Reality) 기술은 사용자에게 컴퓨터 그래픽으로 구성된 가상 세계를 보여줌으로써 다양한 시청각 기반 응용에 적극적으로 활용되는 인터페이스 기술이다. VR 기반 응용은 그래픽 처리 기반 응용이기 때문에 그래픽 처리를 위해 GPU(Graphics Processing Unit)가 장착된 고가의 컴퓨팅 장치가 필수적으로 요구된다. 이는 VR 응용 사용자에게 컴퓨팅 장치의 유지, 관리에 대한 비용 부담을 발생시키며, 이를 해결하는 방법의 하나로써 서비스를 클라우드 환경에서 운용하는 방법이 사용되고 있다. 본 논문에서는 다수의 컨테이너가 VR 응용을 실행하기 위해 GPU를 공유하는 컨테이너 기반 고성능 클라우드 환경에서 GPU 자원 경쟁으로 인해 발생하는 컨테이너 사이의 성능 간섭 문제를 해결하기 위한 성능 관리 기법을 제안한다. 제안하는 기법은 성능 간섭으로 인한 성능 편차를 감소시켜 사용자에게 균일한 성능의 클라우드 기반 원격 VR 서비스를 제공할 수 있도록 지원한다. 또한, 본 논문에서는 실험을 통해 제안하는 기법의 효율성을 검증한다.

• 정보관리학회지
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• 제21권4호
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• pp.133-152
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• 2004

정보시대의 도래로 정보량은 기하급수적으로 증가하게 되었고, 이러한 대량의 정보로부터 이용자 개개인에게 적합한 정보를 적시에 제공할 수 있는 방법으로 SDI 서비스가 연구${\cdot}$개발되어 왔지만, 현실적으로 그 활용도는 매우 낮은 것으로 조사되었다. 이에 본 논문에서는 그 원인을 분석하고 SDI 시스템의 성능을 개선시킬 수 있는 적합성 피드백 기반 SDI 시스템을 개발하고자 하였다. 본 연구의 실험을 위해 개발된 실험시스템은 이용자 최소개입 피드백기반 SDI 시스템, 완전자동 피드백기반 SDI 시스템, 그리고 이용자 최대개입 피드백 기반 SDI 시스템이며, 새로 개발된 3개 시스템의 성능 개선정도를 평가하기 위해 네 번째 시스템으로서 전통적인 SDI 서비스에서 사용하고 있는 방법으로 시스템을 개발하였다. 실험결과 이용자 최대개입 피드백 기반 SDI 시스템이 가장 높은 성능을 보여 주었고, 완전자동 피드백 기반, 이용자 최소개입 피드백기반, 전통적 SDI 시스템 순으로 나타났으며, 피드백기반 시스템들은 피드백이 진행될수록 그 성능이 향상되는 것으로 나타났다.

• 대한인간공학회지
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• 제29권4호
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• pp.527-532
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• 2010

Product developers nowadays must consider not only the technological satisfaction of consumers but their affective needs as well. These affective needs are greatly affected by the appearance and performance functions of the product, which are simply called in this study appearance-based affection and performance-based affection. This study examined these two affective factors that must be considered while designing mobile phones. Extracted relationship between the two factors was processed in five steps. The first step includes gathering potential affective expressions that are needed to evaluate the levels of consumer's affection for mobile phone design in the pool of adjectives. In the second step, a simple frequency analysis was done from a consumer survey to extract frequently used affective expression. The third step was to extract primary tasks for mobile phones and to perform an experiment or a survey for the evaluation of mobile phones using those tasks. Representative affective factors were then extracted in the fourth step based on factor analysis. Finally, using ANOVA, the extracted representative affective factors were prioritized to draw a relationship between appearance-based affection and performance-based affection. The result of this study suggests each of appearance-based affections and performance-based affections that should be considered in designing mobile phones.

• 디지털융복합연구
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• 제11권4호
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• pp.101-108
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• 2013

조직 내 리더십의 중요성에 대한 인식과 더불어 다양한 리더십 관련 연구들이 수행되어 왔었다. 변혁적 리더십, 거래적 리더십, 그리고 윤리 리더십 등에 대한 연구에 비해 진정성 리더십에 관한 연구가 매우 부족한 실정이다. 본 연구의 주요 목적은 진정성 리더십이 종업원의 업무관련 자기 효능감, 역할 성과에 미치는 영향과, 업무관련 자기 효능감이 진정성 리더십이 역할 성과에 미치는 영향 관계에서의 매개역할을 살펴보는 것이다. 연구 목적을 달성하고자 본 연구에서는 선행연구와 실증연구 방법을 병행하였고, 연구결과 진정성 리더십은 종업원의 업무관련 자기 효능감과 역할 성과에 정(+)의 영향을 미치며, 종업원의 업무관련 자기 효능감 역시 역할 성과에 정(+)의 영향을 미치는 것으로 나타났다. 이러한 연구결과는 조직 내 바람직한 리더의 모습이 어떤 것이며, 종업원 성과 향상을 위해 리더가 해야 할 역할에 대해서도 방향을 제시해주고 있다.

• 한국화재소방학회논문지
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• 제33권2호
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• pp.85-97
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• 2019

오늘날 인간의 삶의 질 향상과 다양한 욕구를 충족시키기 위한 건축물은 대형화, 고층화, 심층화, 복합화 되는 추세이며, 이에 따른 비정형화된 공간이 새롭게 창출되면서 성능위주설계대상도 증가하고 있다. 성능위주설계의 피난안전성 평가는 ASET과 RSET를 산정 비교하여 RSET이 ASET를 초과하지 않도록 하여야 한다. 그러나 지하 주차장과 같이 구획된 공간의 면적이 넓고 피난경로가 다양한 경우 현재 시행되고 있는 성능위주설계 평가 방법만으로 모든 피난경로에서 안전성을 확보하기 어려운 문제가 있다. 따라서 본 논문에서는 이러한 문제점을 극복하기 위해 현재 사용되고 있는 성능위주설계의 시뮬레이션 설정방법에 대해 먼저 고찰한 다음 지하 주차장을 대상으로 화재시뮬레이션 2가지와 피난시뮬레이션 3가지 경우를 각각 수행하여 6가지 경우에 대한 피난안전성 평가를 실시하고 비교 평가하여 문제점을 살펴보고 개선된 성능위주설계의 피난안전성 평가 방안을 제시한다.