• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.2
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• pp.251-255
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• 2015

Thermal deformation, such as bending and twisting, occurs among the polymer parts of air-conditioner indoor units because of repetitive temperature change during heating operation. In this study, a numerical method employing finite-element analysis to efficiently simulate the thermal deformation of an assembly is proposed. Firstly, the displacement of an actual assembly produced by thermal deformation was measured using a 3D optical measurement system. The measurement results indicated a general downward sag of the assembly, and the maximum displacement value was approximately 1 mm. The temperature distribution was measured using a thermographic camera, and the results were used as initial-temperature boundary conditions to perform temperature-displacement analysis. The simulation results agreed well with the measured data. To reduce the thermal deformation, the stiffness increased 100%. As the results, the maximum displacement decreased by approximately 5.4% and the twisting deformation of the holder improved significantly.

• Journal of Navigation and Port Research
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• v.28 no.4
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• pp.323-331
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• 2004

This paper introduces a novel approach that can provide the three dimensional information about the movement of a spreader by using two CCD cameras and a laser distance measuring unit in order to derive ALS (Automatic Landing System) in the crane used at a harbor. So far a kind of 2D Laser scanner sensor or laser distance measuring units are used as comer detectors for the geometrical matching between the spreader and a container. Such systems provide only two dimensional information which is not enough for an accurate and fast ALS. In addition to this deficiency in performance, the price of the system is too high to adapt to the ALS. Therefore, to overcome these defects, we proposed a novel method to acquire the three dimensional spreader information using two CCD cameras and a laser distance measuring unit. To show the efficiency of proposed method, real experiments are performed to show the improvement of accuracy in distance measurement by fusing the sensory information of the CCD cameras and a laser distance measuring unit.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.19.1-19.1
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• 2010

The process of manufacturing printed electronics using printing technology is attracting attention because its process cost is lower than that of the conventional semiconductor process. This technology, which offers both a lower cost and higher productivity, can be applied in the production of organic TFT (thin film transistor), solar cell, RFID(radio frequency identification) tag, printed battery, E-paper, touch screen panel, black matrix for LCD(liquid crystal display), flexible display, and so forth. In general, in order to implement printed electronics, narrow width and gap printing, registration of multi-layer printing by several printing units, and printing accuracy of under $20\;{\mu}m$ are all required. These electronic products require high precision to the degree of tens of microns - in a large area with flexible material, and mass productivity at low cost. As such, the roll-to-roll printing process is attracting attention as a mass production system for these printed electronic devices. For the commercialization of this process, two basic electronic ink technologies, such as conductive ink and polymers, and printing equipment have to be developed. Therefore, this paper addressed basis design and test to develop fine patterning equipment employing the roll-to-roll printing equipment and electronic ink.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.140-141
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• 2012

최근 영상분야의 키워드는 초고품질화, 초실감화, 스마트화로 대표될 수 있다. 그 중에서도 무안경식 3D는 초실감화를 이루기 위한 핵심응용분야 중 하나이다. 하지만 무안경식 3D 단말기가 성공적으로 보급되기 위해서는 연구되어야 할 분야가 여전히 존재한다. 그 중에서도 본 논문에서는 고화질의 무안경식 3D 스마트 콘텐츠 제작에 필요한 자동 스테레오 정합 기법을 제안하였다. 이전까지 연구된 변이지도 추출을 위한 알고리즘은 전역적 최적화 방법을 사용할 시 영상의 해상도와 깊이 정도에 따른 연산량의 증가로 많은 수행시간이 요구되었다. 또한 좌/우 영상의 intensity 정보만으로는 정확한 변이지도 추출이 어렵다는 한계점이 존재하였다. 이러한 이유로 본 논문에서는 스트림 영상에서 프레임 간의 정보를 이용하여 신뢰지도와 경계정보를 생성하였으며 belief propagation 스테레오 정합 방법을 이용하여 고화질의 정확한 변이지도를 추출하였다. 또한, 알고리즘의 연산량에 대한 문제를 해결하기 위한 고속화 방안으로, 최근 많은 연구가 이루어지고 있는 GPU(graphics processing units) 를 이용한 병렬처리를 연구하였다. 마지막으로 연구결과의 신뢰성을 향상하기 위하여 다양한 데이터를 이용한 실험을 통해 고화질의 영상정보를 고속으로 추출할 수 있음을 확인하였다.

• Journal of Power Electronics
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• v.3 no.3
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• pp.145-150
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• 2003

Reliability, availability, and cost have been the major concerns for photovoltaic hybrid systems since their beginning as primary sources for much critical applications like communication units and repeaters. This paper descnbes the performance of two hybrid systems, photovoltaic-battery, wind-turbine coupled with the public-grid (PVBWG) hybrid system and photovoltaic-battery, wind-turbine coupled With the diesel generator (PVBWD) hybrid system The systems are sized to power a typical 300W/48V de telecommunication load continuously throughout the year Such hybrid systems consist of subsystems, which in turn consist of components Failure of anyone of these components may cause failure of the entire system. The reliability and availability basics, and estimation procedure for the two proposals are introduced also in this paper. The PVBWG and PVBWD system configurations are shown with the relevant mean-time-between-faIlure (MTBF) and failure rate (${\lambda}$) of each component. The characteristics equations of the two systems are deduced as a function of operating hours and the percentage of sun and wind availabilities per day. The system probability failure as well as the reliability is estimated based on the fault tree analysis technique. The results show that, by using standard or normal components MTBF, the PVBWG is more reliable and the time of periodic maintenance period is more than one year especially in the rich sites of both sun and wind, but PVBWD competes else Also, in the first five years from the system installation, the system is quit reliable and may not require any maintenance. The results show also, as the sun and wind are available, as the system reliable and available.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.5
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• pp.249-256
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• 2000

This paper deals with the control of the lateral motion of a mobile vehicle. A mobile vehicle using in this experiment is able to adapt many unmanned automatic driving system, for example, like a automated product transporting system. This vehicle is consist of the two servomotors. One is used to accelerate this vehicle and the another is used to change this lateral direction. An adaptive fuzzy logic controller(AFLC) is designed and applied to a experimental mobile vehicle in order to achieve the control of the lateral direction. An adaptive fuzzy logic controller(AFLC) is designed and applied to a experimental mobile vehicle in order to achieve the control of the lateral motion of the vehicle. Therefore, the main aim of this paper is investigate the possibility of applying adaptive fuzzy control algorithms to a microprocessor-based servomotor controller which requires faster and more accurate response compared with many other industrial processes. Fuzzy control rules are derived by modelling an expert's driving actions. Experiments are performed using a mobile vehicle with sensing units, a microprocessor and a host computer.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.441-446
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• 2007

This present study is to evaluate the cooling performance of a water-to-refrigerant ground source heat pump system(GSHP) under actually operating condition. 1 unit is selected among 10 units of the GSHP in the building to analyze the performance. The average cooling COP of the GSHP at the part load of 64% is 8.2, overall system COP is 6.19. In the GSHP system, the cooling temperature of the condenser is lower compared to the air source heat pump system. Conclusively, the cooling performance of the GSHP is higher than the air source heat pump system by 80%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.6
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• pp.1545-1559
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• 2023

In the cloud environment, microservices are implemented through Kubernetes, and these services can be expanded or reduced through the autoscaling function under Kubernetes, depending on the service request or resource usage. However, the increase in the number of nodes or distributed microservices in Kubernetes and the unpredictable autoscaling function make it very difficult for system administrators to conduct operations. Artificial Intelligence for IT Operations (AIOps) supports resource management for cloud services through AI and has attracted attention as a solution to these problems. For example, after the AI model learns the metric or log data collected in the microservice units, failures can be inferred by predicting the resources in future data. However, it is difficult to construct data sets for generating learning models because many microservices used for autoscaling generate different metrics or logs in the same timestamp. In this study, we propose a cloud data refining module and structure that collects metric or log data in a microservice environment implemented by Kubernetes; and arranges it into computing resources corresponding to each service so that AI models can learn and analogize service-specific failures. We obtained Kubernetes-based AIOps learning data through this module, and after learning the built dataset through the AI model, we verified the prediction result through the differences between the obtained and actual data.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.1
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• pp.37-47
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• 2008

Exploitation of address generation units which are typically provided in DSPs plays an important role in DSP code generation since that perform fast address computation in parallel to the central data path. Offset assignment is optimization of memory layout for program variables by taking advantage of the capabilities of address generation units, consists of memory layout generation and address pointer assignment steps. In this paper, we propose an effective address pointer assignment method to minimize the number of address calculation instructions in DSP code generation. The proposed approach reduces the time complexity of a conventional address pointer assignment algorithm with fixed memory layouts by using minimum cost-nodes breaking. In order to contract memory size and processing time, we employ a powerful pruning technique. Moreover our proposed approach improves the initial solution iteratively by changing the memory layout for each iteration because the memory layout affects the result of the address pointer assignment algorithm. We applied the proposed approach to about 3,000 sequences of the OffsetStone benchmarks to demonstrate the effectiveness of the our approach. Experimental results with benchmarks show an average improvement of 25.9% in the address codes over previous works.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.11
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• pp.41-47
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• 2016

High efficiency video coding (HEVC) employs a coding tree unit (CTU) to improve the coding efficiency. A CTU consists of coding units (CU), prediction units (PU), and transform units (TU). All possible block partitions should be performed on each depth level to obtain the best combination of CUs, PUs, and TUs. To reduce the complexity of block partitioning process, this paper proposes the PU mode skip algorithm with region of interest (RoI) selection using motion vector. In addition, this paper presents the CU depth level skip algorithm using the co-located block information in the previously encoded frames. First, the RoI selection algorithm distinguishes between dynamic CTUs and static CTUs and then, asymmetric motion partitioning (AMP) blocks are skipped in the static CTUs. Second, the depth level skip algorithm predicts the most probable target depth level from average depth in one CTU. The experimental results show that the proposed fast CU decision algorithm can reduce the total encoding time up to 44.8% compared to the HEVC test model (HM) 14.0 reference software encoder. Moreover, the proposed algorithm shows only 2.5% Bjontegaard delta bit rate (BDBR) loss.