• Nuclear Engineering and Technology
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• 제14권1호
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• pp.1-9
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• 1982

이 논문에서는 Sargent & Lundy 회사로부터 입수한 발전소 설계 인력 분포에 관한 49개 실적치 커브와 Bechtel사가 제안한 수 개의 모델 커브를 분석하였다. 이들 커브로 부티 발전소 설계에 소요되는 인력분포를 Gamma분포로 가정하고 그 확률함수를 하나의 모델커브로 선정하였다. 이 모델커브를 이용하여 정부의 장기 원자력 발전소 설계계획에 따른 인력 수요를 년도별로 산출하였다. 또한 감응도 분석의 하나로서 엔지니어들의 숙련도에 따른 설계 인력 수요의 변화를 분석하였다.

• 한국지능시스템학회논문지
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• 제19권5호
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• pp.699-705
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• 2009

본 논문은 지게차 AGV(autonomous ground vehicle)의 자율주행을 위한 제어 방법에 관한 연구이다. 기존에 개발된 지게차 AGV의 위치측정 방법으로는 자기-자이로 유도(magnet-gyro guidance) 방식과 유선 유도(wire guidance) 방법이 있지만, 유지보수에 대한 지속적인 노력과 비용문제가 있으며, 작업 환경의 변화에 따라 작업 환경을 재구성해야하는 단점이 있다. 따라서 본 논문에서는 외란에 강인하고 작업 환경 및 작업 내용의 변경에 유연한 시스템을 구축하기 위해 레이저 내비게이션 센서와 엔코더, 자이로 센서의 센서융합을 통한 위치측정 시스템을 개발하였다. 또한 팔레트를 하역 운송해야하는 지게차 AGV의 주행제어를 위해 팔레트와 지게차 AGV 사이의 거리 차와 각도 차를 바탕으로 퍼지 제어 및 비례 제어를 이용한 주행제어기를 설계하였다. 본 연구에서 제안한 지게차 AGV를 위한 제어 시스템의 성능 분석을 위해 물류 운송작업이 가능한 작업공간에서 동일한 하역 작업을 10회 반복 하였다. 그 결과, 시뮬레이션에 의해 생성된 경로와 실제 주행경로의 최대 평균 오차가 87.77mm를 가짐을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.155.1-155
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• 2001

The main contribution of this research is that it gives:(1) a rational criterion to select the best self-localizing method for a particular situation, and (2) an appropriate arrangement of the landmarks to minimize the error. In this paper, the authors propose a set of indices to evaluate the accuracy of the self-localizing methods, and the indices are derived from a sensitivity which is defined as the ratio of the localizing error to sensor error. And then, we compare the accuracy of self-localizing a mobile robot with landmarks based on the indices, and propose a rational way to minimize the localizing error.

• 로봇학회논문지
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• 제4권1호
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• pp.1-9
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• 2009

Radio Frequency Identification (RFID) is an automatic identification method. Information such as identification, logistics history, and specification of products are written and stored into the memory of RFID tags (that is, transponders), and retrieved through RF communication between RFID reader device and RFID tags. RFID systems have been applied to many fields of transportation, industry, logistics, environment, etc in order to improve business efficiency and reduce maintenance cost as well. Recently, some research results are announced in which RFID devices are combined with other sensors for mobile robot localization. In this paper, design of multi-protocol baseband for RFID reader device is proposed, and the baseband modem is implemented into SoC (System On a Chip). The baseband modem SoC for multi-protocol RFID reader is composed of several IP (Intellectual Property) blocks such as multi-protocol blocks, CPU, UART(Universal Asynchronous Receiver and Transmitter), memory, etc. As a result, the SoC implemented with FPGA(Field Programmable Gate Array) is applied to real product. It is shown that the size of RFID Reader module designed with the FPGA becomes smaller, and the SoC chip price for the same function becomes cheap. In addition, operation performance could be the same or better than that of the product with no SoC applied.

• 유통과학연구
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• 제10권11호
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• pp.21-30
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• 2012

Purpose - This study aimed to analyze the strategy of late domestic entrants into the Chinese retail market, focusing on the case of Lotte-Mart, given that there are few studies on market entry strategies of domestic retail companies in China. Research Design, data, methodology - The methodology of this paper is a case study approach, focusing on literature reviews and a few interviews. We conducted a survey by disseminating questionnaires and conducting interviews focusing on the Chinese retail market, and analyzed Lotte-Mart's market entry strategy in China. Results - Lotte-Mart chose M&A as the mode of entry, pursuing quick market entry and rapid expansion. It chose small to medium size cities with relatively less competition. Subsequently, Lotte-Mart devoted significant effort towards localization, attempting to organize stores and assorting products to fit the Chinese consumers' preferences. It operated CSR programs to increase its brand awareness and to create a favorable brand image. Conclusions - Lotte-Mart now needs to devise alternative corporate strategies for business expansion and growth. An understanding of the Chinese retail market and the case study analysis of Lotte-Mart's market entry strategy offers significant insights for domestic retail companies looking to expand into China.

• 제어로봇시스템학회논문지
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• 제18권2호
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• pp.126-132
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• 2012

The technique for estimation of sound source direction is one of the important methods necessary for various engineering fields such as monitoring system, military services and so on. As a new approach for estimation of sound source direction, this paper propose the bio-mimetic localization sensor based on mechanically coupling structure motivated by hearing structure of fly, Ormia Ochracea. This creature is known for its outstanding recognition ability to the sound which has large wavelength compared to its own size. ITTF (Inter-Tympanal Transfer Function) which is the transfer function between displacements of the tympanal membranes on each side has the all inter-tympanal information dependent on sound direction. The peak and notch features of desired ITTF can be generated by using the appropriate mechanical properties. A example of estimation of sound source direction using generated ITTF with monotonically changing notch and peak patterns is shown.

• 로봇학회논문지
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• 제11권2호
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• pp.60-72
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• 2016

This study proposes a multi-robot system, using multiple autonomous robots, to explore concrete structures and assist in their maintenance by sealing any cracks present in the structure. The proposed system employed a new self-localization method that is essential for autonomous robots, along with a visualization system to recognize the external environment and to detect and explore cracks efficiently. Moreover, more efficient crack search in an unknown environment became possible by arranging the robots into search areas divided depending on the surrounding situations. Operations with increased efficiency were also realized by overcoming the disadvantages of the infeasible logical behavioral model design with only six basic behavioral strategies based on distributed control-one of the methods to control swarm robots. Finally, this study investigated the efficiency of the proposed multi-robot system via basic sensor testing and simulation.

• 반도체디스플레이기술학회지
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• 제23권1호
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• pp.71-78
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• 2024

In indoor environments, since global positioning system (GPS) signals can be blocked by obstacles, such as building structure. the performance of GPS-based positioning methods can be degraded because of the loss of GPS signals. To solve this problem, various localization schemes using inertial measurement unit (IMU) sensors, such as gyroscope, accelerometer, and magnetometer, have been proposed to enhance the positioning accuracy in indoor environments. IMU-based positioning methods can estimate the location of the user by calculating the velocity and heading angle of the user without the help of GPS. However, low-cost MEMS IMUs may lead to drift error and large bias. In addition, positioning errors in IMU-based positioning approaches can be caused by the irrelevant motion of the pedestrian. In this study, we propose an enhanced indoor positioning method that provides more reliable localization results by using the camera, light detection and right (LiDAR), and ARKit framework on the iPhone. Through reliable positioning results and augmented reality (AR) experiences, our indoor positioning system can provide indoor space guidance services.

• 산경연구논집
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• 제9권2호
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• pp.7-16
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• 2018

Purpose - This research addresses the question of how an international retailer like Costco can succeed in a foreign mature market and satisfy the local consumers. Our study aims to promote our understanding of how foreign retailers influence local consumers in a mature market with differentiated business models. Research design, data, and methodology - Our study uses company publications, secondary sources of information and the results of a questionnaire survey consisting of 106 participants. Consumer responses were solicited through a questionnaire survey conducted in the city of Kobe in December of 2013. Results - Product differentiation from local retailers in a mature market like Japan gave Costco a competitive edge. Compared with local supermarkets, Costco was preferred by Japanese consumers for its variety of goods that it carries, as well as in-store promotion large package of selling units, in-store amenities, and customer services. Conclusions - First, a theoretical framework is proposed in this study that can aid in developing localization strategies in a mature market such as Japan. Second, it reveals that an international retailer can succeed in a foreign market by stimulating local consumers to change their purchasing behavior, without having to alter the prevailing format of operation.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 추계종합학술대회
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• pp.457-461
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• 2007

In many applications, received signal strength indicator is used for location tracking and sensor nodes localization. For location finding, the distances between sensor nodes can be estimated by converting received signal's power into distance using path loss prediction model. Many researches have done the analysis of power-distance relationship for radio channel characterization. In indoor environment, the general conclusion is the non-linear variation of RSSI values as distance varied linearly. This has been one of the difficulties for indoor localization. This paper presents works on indoor RSSI characterization based on statistical methods to find the overall trend of RSSI variation at different places and times within the same room From experiments, it has been shown that the variation of RSSI values can be determined by both spatial and temporal factors. This two factors are directly indicated by the two main parameters of path loss prediction model. The results show that all sensor nodes which are located at different places share the same characterization value for the temporal parameter whereas different values for the spatial parameters. Using this relationship, the characterization for location estimation can be more efficient and accurate.