• 항공우주시스템공학회지
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• 제10권1호
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• pp.35-42
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• 2016

Bearing friction and disturbance are the important parameters in control spacecraft using reaction wheel. In this paper, those parameters are estimated by preload and oil quantity. In order to determine the bearing preload's impact on performance, measure the disturbance and the bearing friction coefficient with increasing the preload to the allowed amount. And, find the relationship between oil quantity and bearing friction coefficient, measure it with increasing the oil amount in the bearing. With these results as a reference, find the appropriate amount of preload and oil quantity.

• Journal of information and communication convergence engineering
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• 제19권4호
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• pp.221-227
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• 2021

An early warning system was developed to help identify stock status as early as possible. For performance to improve, there needs to be a feature to predict the amount of stock that must be provided and a feature to estimate when to buy goods. This research was conducted to improve the inventory early warning system and optimize the Reminder Block's performance in minimum stock settings. The models used in this study are the single exponential smoothing (SES) method for prediction and the economic order quantity (EOQ) model for determining the quantity. The research was conducted by analyzing the Reminder Block in the early warning system, identifying data needs, and implementing the SES and EOQ mathematical models into the Reminder Block. This research proposes a new Reminder Block that has been added to the SES and EOQ models. It is hoped that this study will help in obtaining accurate information about the time and quantity of repurchases for efficient inventory management.

• 한국시뮬레이션학회논문지
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• 제6권2호
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• pp.71-79
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• 1997

In this paper, operations system was designed for the centralization of data processing of various state information from the facilities of mobile communication network. And the system performance experimental system module was measured and analyzed from the designed experimental system module. The configuration of system design was presented with the centralized type to monite and control the facilities of mobile communication network in the central office. The communication process design of the internal system was implemented with the resource of message queue having a excellent transmission ability for processing of a great quantity of information in the inter-process communication among communication resources of UNIX system. The process with a server function from the internal communication processes was constructed with a single server or a double server according to the quantity of operations and implemented with the policy of the presented server. And then, we have measured performance elements in accordance with the change of input parameters from the designed experimental module : response time, waiting time, buffer length, the maximum quantity existing in message queue. And from these results, we have compared and analyzed the system state each server algorithm according to performance variations.

• Design & Manufacturing
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• 제13권3호
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• pp.41-47
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• 2019

In conventional machining, the use of cutting fluid is essential to reduce cutting heat and to improve machining quality. However, to increase the performance of cutting fluids, various chemical components have been added. However, these chemical components during machining have a negative impact on the health of workers and cutting environment. In current machining, environment-friendly machining is conducted using MQL (minimum quantity lubrication) or cryogenic air spraying to minimize the harmful effects. In this study, the injection nozzle that can combined injecting minimum quantity lubrication(MQL) and cryogenic gas was designed and the shape optimization was performed by using computational fluid dynamics(CFD) and design of experiment(DOE). Performance verification was performed for the designed nozzle. The diameter of the sprayed fluid at a distance of 30 mm from the nozzle was analyzed to be 21 mm. It was also analyzed to lower the aerosol temperature to about 260~270K.

• 한국정보시스템학회지:정보시스템연구
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• 제23권2호
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• pp.91-107
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• 2014

In computer-mediated idea generation where contributions can be anonymous, the ability to accurately monitor performances is limited, inducing social loafing. Prior research has suggested that social loafing is likely an important factor in reducing task performance. Researchers have theorized that loafing could be minimized if clear performance feedback is provided. Our prior study evidences a substantial performance gain by the provision of real time performance information about who is contributing and who is not. However, our prior study incorporated the quantity feedback only to create a larger pool of ideas based on the long-standing assumption (i.e., quantity breeds quality), not considering the quality feedback. As a result, taking advantage of anonymity in the form of pseudonymity, individuals in almost all groups exhibited a tendency of self-presentation by capitalizing on ideas of which quality was low and even frivolous (i.e., junk comments) toward the later stages of the session. Thus, we have learned that the quantity performance feedback alone does not have enough restrictiveness to consistently control the performance behavior throughout the session. Since a process chart allows participants to monitor process variation by comparing new performance data to past performance data, we incorporated real-time visual process performance feedback to reveal performance histories by connecting the sequence of idea quality scores in a time-series format. Using this environment, a laboratory experiment was conducted with five-member groups that examined the influence of both identifiability (i.e., anonymity versus pseudonymity) and process performance feedback (i.e., yes or no) in a $2{\times}2$ factorial design. The result showed that groups in the process performance feedback treatment outperformed groups in the no feedback treatment. Additionally, process performance feedback and identifiability interacted such that groups in the process performance feedback/pseudonymity treatment had the highest performance. The implications of these findings for future research, as well as the implications for the design of group idea generation procedures are discussed.

• 한국콘텐츠학회논문지
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• 제14권12호
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• pp.655-664
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• 2014

최근 많은 기업들이 팀제를 활용하고 있지만 팀의 업무 수행 향상에 효과적이고 효율적인 피드백 제공방법에 대한 연구는 부족한 상황이다. 이에 본 연구의 목적은 팀 수행 상황에서 개인 피드백과 집단 피드백이 과업 수행의 양과 질에 미치는 효과를 비교하는 것이었다. 실험 과제는 영어 문서를 컴퓨터에 입력하는 것이었고 수행의 양은 입력된 단어의 수로, 수행의 질은 올바르게 입력된 단어의 비율로 측정되었다. 혼합설계(mixed design)가 적용되었고 총 48명의 참가자들은 개인과 집단 피드백 집단에 무선적으로 할당되었다. 각 팀은 3명으로 구성되었고 총 4회기 동안 함께 과제를 수행하였다. 개인피드백 조건에서는 각 참가자에게 개인의 수행에 대한 정보만 제공되었고, 집단 피드백 조건에서는 팀의 전체 수행 합에 대한 정보만을 제공하였다. 참가자들의 타이핑 속도를 통제한 공변량 분석결과, 두 가지 피드백 모두 수행의 양을 증가시키는 데 효과적이었지만, 효과크기는 집단 피드백이 더 높았다. 수행의 질에 있어서는 집단 피드백 조건에서만 올바르게 입력한 비율이 유의미하게 증가하였다. 따라서 개인 피드백 보다는 집단 피드백이 과업 수행 증가에 좀 더 효과적, 효율적이라고 할 수 있다. 하지만 본 연구결과는 기존의 연구결과와는 상반된 결과로 일반화하기 위해서는 더 많은 관련 연구가 필요하다. 특히 후속연구에서는 문화 차이, 과제 종류에 대한 고려가 필요하다.

• 설비공학논문집
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• 제1권4호
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• pp.313-318
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• 1989

Experiments have been performed to find an optimum filling quantity of working fluid in a heat pipe. The optimum operation has been defined to give a minimum temperature difference between evaporator and condenser. The experimental results show that there exists an optimum filling quantity which is slightly smaller than that calculated by the well known formula from the geometry of the wick. When the concaved vapor-liquid interface at the wick is taken into account to calculate the required quantity of working fluid, the computed value agrees with the experimentally determined quantity.

• Management Science and Financial Engineering
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• 제16권3호
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• pp.21-47
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• 2010

Quantity discounts provide a practical foundation for supply chain inventory policies, improving the supplier's profit and reducing the buyer's inventory cost simultaneously. Traditional quantity-discount research, which deals with inventory coordination between a buyer and a supplier, is extended to a stationary stochastic environment. This research shows that the magnitude of the optimal discounts scheduled by the deterministic quantity discount models may not be large enough to cover the buyer's additional inventory stocking risks under uncertain conditions. As a result, the buyer's total inventory cost may often increase rather than decrease. In contrast, the proposed model allows the supplier to identify the discount level, which shares the buyer's amplified risk associated with temporary overstocking and ensures that both buyer and supplier benefit economically. The performance of the proposed model was tested in the continuous review environments via numerical experiments. The experimental results support the proposed method as a feasible alternative in coordinating inventory decisions under stochastic demand.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.379-382
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• 2008

잡음환경 하의 회화에서 잡음량을 줄이고 신호처리 시스템의 성능을 향상시키기 위해서는 잡음량에 따라서 적응적으로 처리되는 신호처리 시스템이 필요하다. 따라서 본 논문에서는 선형예측계수를 사용하여 잡음량을 인식하는 방법을 제안하며, 본 잡음량 인식은 다양한 배경잡음에 의하여 열화된 3종류의 음성이 신경회로망에 의하여 학습되어진다. 본 실험에서는 Aurora2 데이터베이스를 사용하여 여러 잡음에 대하여 평균적으로 약 97.6% 이상의 양호한 인식결과를 확인할 수 있었다.

• 경영정보학연구
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• 제19권2호
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• pp.71-94
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• 2017

추천 시스템은 정보 과부하를 줄여 선택의 질을 높이는 기술로 다양한 분야에서 활용되고 있다. 기존의 추천 시스템 연구는 주로 영화나 음악과 같은 단순한 콘텐츠 추천을 대상으로 했으며, 추천 수량과 기존에 경험했던 상품의 재 추천이 고려되지 않았다. 하지만 다양한 분야에서 추천 시스템의 수요가 증가함에 따라 추천 수량과 재 추천을 고려한 보다 범용적이고 확장된 추천 시스템 개발이 필요한 시점이다. 또 기존 추천 시스템은 온라인 상에서 개별 고객을 대상으로 하는 경우가 많았는데, 오프라인 상에서 개별 고객이 아닌 매장에도 추천 시스템을 적용할 수 있다. 본 연구에서는 추천 시스템 분야에서 많이 활용되는 사용자 기반 협업 필터링 알고리즘에서 추천 수량과 재 추천을 고려하는 방법을 제안하고, 이를 오프라인 의류 매장의 재고 관리 문제에 적용함으로써 다양한 분야에 추천 시스템을 활용할 수 있음을 보인다. 제안한 방법을 통해 각 매장에 수요가 높을 것으로 예측되는 상품과 예상 판매 수량을 예측하여, 해당 상품을 진열할 것을 추천하며, 이는 MAE, Precision, Recall, F1 measure 관점에서 기준 모델보다 추천 성능이 더 뛰어나다. 또 성능을 평가하기에 적합한, 추천 수량 부족과 초과에 따른 페널티를 고려하는 새로운 Quantity Precision, Quantity Recall, Quantity F₁ measure 계산 방식을 제안한다. 마지막으로 참신성 관점에서 제안한 방법의 신규 매출 창출 효과를 평가한다. 본 연구는 추천 수량과 재 추천을 고려했다는 점, 온라인이 아닌 오프라인 데이터를 사용했다는 점, 개별 고객이 아닌 매장을 추천 대상으로 했다는 점에서 기존 추천 시스템 연구와는 차별되는 의의를 가진다. 나아가 본 연구에서 제안한 방법론은 재고 관리 이외에도 추천 수량과 재 추천을 고려하는 다양한 분야에 적용될 수 있는 범용성을 가진다.