• The Korean Journal of Physiology and Pharmacology
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• 제2권1호
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• pp.77-84
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• 1998

Ureteral obstruction causes increase in renal blood flow (RBF) and partial impairment of the autoregulation of RBF. Although increased renal prostaglandin production is responsible for the former, it is not clear whether or not it is also responsible for the latter. Therefore, we investigated the role which prostaglandins play in the autoregulation of RBF during an ureteral pressure elevation (40 $cmH_2O$). Since the major mechanism of RBF autoregulation is the tubuloglomerular feedback, studying the interaction between ureteral pressure and RBF autoregulation may reveal the role of prostaglandin in tubuloglomerular feedback. To pursue the purpose, six anesthetized dogs were prepared for the measurements of RBF, mean sytemic and renal arterial pressure (RAP) and the manipulation of ureteral pressure. The autoregulation curves were determined during both control and elevation of the ureteral pressure, before and after the pretreatment with indomethacin, a cyclooxygenase inhibitor. The desired ureteral pressure was achieved by vertically elevating the water-filled reservoir connected to the ureteral catheter to 40 cm above the kidney level. In response to the elevation of the ureteral pressure, RBF increased from $170{\pm}8 ml{\cdot}min^{-1}\;to\;189{\pm}8$, and the systemic arterial pressure didn't change significantly. During spontaneous urine flow, RBF autoregulation was abolished when RAP was reduced to $59{\pm}3$ mmHg. On the other hand, during the ureteral pressure elevation, the autoregulation curves shifted upward and rightward from control, and the pressure when RBF autoregulation was abolished was $74{\pm}3$ mmHg. The pretreatment of the dogs with indomethacin failed to affect the lower limit of RBF autoregulaion during both control ($63{\pm}5$ mmHg) and the elevated ureteral pressure ($77{\pm}5$ mmHg). Since RBF failed to increase in response to the elevated ureteral pressure, RBF autoregulation curves obtained during the elevated ureteral pressure shifted only rightward from indomethacin control. The results indicate that the increased intrarenal level of prostaglandin or prostaglandin-induced vasodilation does not appear to bear any relation to the reduction in the autoregulatory capacity during partial ureteral obstruction. It seems that the partial impairment of the autoregulation during acute ureteral obstruction is due to the consumption of tubuloglomerular feedback mechanism at spontaneous RAP and that prostaglandin is neither mediator nor effector of tubuloglomerular feedback mechanism.

• 벤처창업연구
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• 제16권6호
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• pp.269-285
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• 2021

조직 내 개인 및 개별 기기에 산재 되어 있는 지식의 체계적 관리가 조직의 지속적 성장을 위한 핵심 요인으로 인식되면서, 조직들은 지식경영에 대한 관심을 높이고 있다. 하지만, 조직 지식경영의 지속적 운영은 지식을 생산하는 구성원의 능동적인 공유 행동을 필수적으로 요구하지만, 리더 및 조직원의 참여 부족과 같은 이유로 실패 사례들이 제시되고 있다. 본 연구는 지식 생산 역량이 상대적으로 부족한 중소기업 내 리더의 진성 리더십이 조직에 대한 가치 인식을 통해 개인의 지식공유 의도로 이어지는 메커니즘을 제시하는 것을 목적으로 한다. 또한, 업무적 활동의 상호교환 관점에서 상호피드백과 업무 상호의존성이 지식공유 의도에 미치는 영향을 조절하는 것을 확인한다. 연구는 선행연구를 기반으로 연구 모델을 도출하였으며, 지식경영 정책을 도입한 중소기업에 근무하는 직원들을 대상으로 설문을 실시하여 272개의 표본을 확보하였다. 또한, 연구는 AMOS 22.0 기반의 구조방정식모델링을 적용하여 가설을 검증하였다. 연구 결과는 진성 리더십이 조직 동일시와 조직 몰입을 매개로 지식공유 의도에 긍정적 영향을 미치는 것을 확인하였으며, 상호피드백과 업무 상호의존성이 지식공유 의도에 영향을 주는 선행요인들에 대한 조절 효과를 가지는 것을 확인하였다. 본 연구는 중소기업의 리더의 진정성 있는 행동이 구성원의 지식공유 행동에 미치는 절차를 제시하고, 업무적 협력이 절차의 영향을 강화하는 것을 제시하였기 때문에, 지식경영을 위해 중소기업 리더와 조직 차원에서 접근해야 할 행동 방향을 제시한다.

• 한국비블리아학회지
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• 제16권1호
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• pp.247-267
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• 2005

이 연구는 부 단위의 중앙행정부처 웹사이트 21개 기관과 청 단위 중앙행정부처 웹사이트 18개 기관을 대상으로 웹 정보제공 서비스에 대한 평가연구를 수행하였다. 분석에 사용된 평가기준은 정보의 내용, 전자적 민원처리, 전자적 의견수렴, 접근 및 이용편의성, 디자인 항목으로서 세부항목 26개 항목에 걸쳐서 평가가 진행되었다. 모든 항목에서 부단위의 중앙행정부처 웹사이트의 성능이 청 단위 중앙행정부처 웹사이트의 성능보다 우수한 것으로 나타났다. 제언으로는 공개정보의 활성화를 위한 노력, 기관별 특성화된 정보제공, 기술향상에 더욱 투자할 것, 행정관료의 적극적인 자세 촉구 등이 제기되었다.

• 제어로봇시스템학회논문지
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• 제4권4호
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• pp.464-478
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• 1998

In teleoperation, it is important for an operator to feel as if he really were in a distant place. To realize this objective, the various information from a remote site must be presented to the operator. Even though tactile information is very important to efficiently execute a task, it is not yet sufficiently provided for the operator. In this paper, we propose the new mechanism that can provide the more dexterous tactile information to the operator This device utilizing the electromagnetic force is designed to be compact and light enough to be attached to the fingerpad, and designed to be controlled continuously. The magnetic circuit is derived by the probable flux paths method in order to take forces at any given dimension. An optimization technique is also proposed to maximize the tactile force that humans can perceive under the same conditions. The objective function is formulated as maximizing displacements indented on the fingerpad, considering the mechanism of human tactile perception. The optimization formulation is subject to the geometric and rising temperature constraints in the coil. It is demonstrated that, by optimization, the tactile force increases by 24%, compared with that obtained from the initial design.

• The Journal of Asian Finance, Economics and Business
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• 제7권9호
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• pp.505-516
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• 2020

The purpose of the research is to identify antecedents of mobile wallet continuance intention in Vietnam. A self-administered questionnaire was distributed to collect data from a total of 276 respondents. Partial least squares structural equation modeling was employed for analyzing the data. Five mobile wallet features - mobile application quality, mobile wallet familiarity, situational normality, payment security, and feedback mechanism - are introduced as fundamental elements, which influence customer' continuance intention to use mobile wallet in Vietnam. The results indicate that mobile quality application and familiarity can significantly influence perceived ease-of-use (PEOU) and perceived usefulness (PU), but situational normality has an impact only on PEOU. PEOU and PU are positively related to satisfaction. On the other hand, payment security and feedback mechanism affect positively customer' trust. As a result, the positive effects that satisfaction and trust have on electronic wallet continuance intention are confirmed. The findings can be used to advise mobile wallet providers to improve their platform design and services to retain users. As a theoretical contribution, this study combines the Technology Acceptance Model, Unified Theory of Acceptance and Use of Technology to investigate the key determinants on continuance intention in the context of electronic wallet in Vietnam.

• 생물정신의학
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• 제19권3호
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• pp.121-127
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• 2012

Objectives : The multimodal telepresence systems have been adopted in a variety of applications, such as telemedicine, space or underwater teleoperation and videoconference. Multimedia, one of the telepresence systems, has been used in various fields including entertainment, education and communication. The degree of subjective telepresence is defined as the probability that a person perceives to be physically in the remote place when he/she experiences a multisensory feedback from the multimedia. The current study aimed to explore the neural mechanism of telepresence related to multisensory feedback in patients with schizophrenia. Methods : Brain activity was measured using functional magnetic resonance imaging while fifteen healthy controls and fifteen patients with schizophrenia were experiencing filmed referential conversation at various distances (1 m, 5 m and 10 m). Correlations between the image contrast values and the telepresence scores were analyzed. Results : Subjective telepresence was not significantly different between the two groups. Some significant correlations of brain activities with the telepresence scores were found in the left postcentral gyrus, bilateral inferior frontal gyri, right fusiform gyrus, and left superior temporal sulcus. There were no main effects of group and distance. Conclusion : These results suggest that patients with schizophrenia experience telepresence as appropriately as healthy people do when exposed to multimedia. Therefore, patients with schizophrenia would have no difficulty in immersing themselves in multimedia which may be used in clinical training therapies.

• 한국콘텐츠학회논문지
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• 제21권12호
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• pp.896-905
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• 2021

인공지능 기반 보안관제 시스템은 운영환경에서 발생할 수 있는 학습 데이터 오류, 신규 공격 이벤트 발생으로 인한 오탐 증가 등 문제를 해결하기 위해 피드백 기능이 연구되고 있다. 그러나 한정된 관제 인력의 피드백 수행 방식은 모델 개선에 오랜 시간이 걸리고 숙련되지 않은 관제 인력의 피드백은 오히려 모델 성능 저하의 원인이 될 수 있다. 본 논문에서는 관제 인력 한계 극복, 신규 오탐 개선, 빠른 모델 성능 향상을 위한 능동형 보안관제 모델 개선 프로세스를 제안하였다. 운영 중 예측된 유사 이벤트를 군집화 하고, 피드백이 우선적으로 필요한 군집을 계산하여 운영자에게 대표 이벤트 설명이 가능한 인공지능(eXplainable AI) 기반 시각화도 함께 제시하였다. 수신된 대표 피드백은 동일 군집과 다른 데이터를 계산하여 제외하고 피드백 전파 학습 데이터를 생성한다. 준비된 학습 데이터는 초기 모델과 함께 점진적 학습을 통해 모델을 생성함으로써 성능을 향상시키는 프로세스이다. 제안 프로세스의 실효성 검증을 위해 웹 어플리케이션 방화벽 데이터셋 PKDD2007과 CSIC2012를 선택하여 3개의 시나리오를 통해 실험을 진행하였다. 실험 결과 제안된 프로세스는 피드백을 주지 않았거나 소수 운영자 피드백을 적용한 모델 성능에 비해 모든 지표에서 약 30% 이상의 성능 향상을 확인하였다.

• Journal of Computational Design and Engineering
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• 제3권4호
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• pp.312-321
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• 2016

Dynamic behaviour of a slider-crank mechanism associated with a smart flexible connecting rod is investigated. Effect of various mechanisms' parameters including crank length, flexibility of the connecting rod and the slider's mass on the dynamic behaviour is studied. Two control schemes are proposed for elastodynamic vibration suppression of the flexible connecting rod and also obtaining a constant angular velocity for the crank. The first scheme is based on feedback linearization approach and the second one is based on a sliding mode controller. The input signals are applied by an electric motor located at the crank ground joint, and two layers of piezoelectric film bonded to the top and bottom surfaces of the connecting rod. Both of the controllers successfully suppress the vibrations of the elastic linkage.

• 한국시스템다이내믹스연구
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• 제11권2호
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• pp.77-102
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• 2010

This paper examines a mechanism of the Electronic Territory Expansion and the Information-oriented Society. Especially, a strategy for the territory development based on intelligence is suggested. The strategy is divided into a strategy for the domestic electronic territory and a plan for the global electronic territory. To examine the strategy and the plan, this paper is using the causal map analysis based on the System Thinking Approach. The causal map of the mechanism is characterized by a positive feedback loop. The paper has concluded that it is important to make the positive loops as a virtuous circle. It means that when a society dominates the advantageous position firstly in the field of intelligent and electronic territory, the competitiveness can grow in arithmetical progression.

• Journal of Mechanical Science and Technology
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• 제20권11호
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• pp.1834-1847
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• 2006

A robust minimum-time control (RMTC) strategy is addressed and it is extended to the dual-stage servo design. Rather than conventional switching type sub-optimal controls, it is a reference following control approach where the predetermined minimum-time trajectory (MTT) is tracked by the perturbation compensator based feedback controller. First, the minimum-time trajectory for a mass-damper system is derived. Then, the perturbation compensator to achieve robust tracking performance in spite of model uncertainty and external disturbance is suggested. The RMTC is also applied to the dual-stage positioner which consists of coarse actuator and fine one. To best utilize the actuation redundancy of the dual-stage mechanism, a null-motion controller to actively regulate the relative motion between the two stages is formulated. The performance of RMTC is validated through simulation and experiment.