• International journal of advanced smart convergence
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• 제12권4호
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• pp.164-170
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• 2023

With the recent advances in AI (artificial intelligence) and HPC (high-performance computing) technologies, deep learning is proliferated in various domains of the 4th industrial revolution. As the workload volume of deep learning increasingly grows, analyzing the memory reference characteristics becomes important. In this article, we analyze the memory reference traces of deep learning workloads in comparison with traditional workloads specially focusing on read and write operations. Based on our analysis, we observe some unique characteristics of deep learning memory references that are quite different from traditional workloads. First, when comparing instruction and data references, instruction reference accounts for a little portion in deep learning workloads. Second, when comparing read and write, write reference accounts for a majority of memory references, which is also different from traditional workloads. Third, although write references are dominant, it exhibits low reference skewness compared to traditional workloads. Specifically, the skew factor of write references is small compared to traditional workloads. We expect that the analysis performed in this article will be helpful in efficiently designing memory management systems for deep learning workloads.

• Journal of Positioning, Navigation, and Timing
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• 제11권4호
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• pp.369-379
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• 2022

In weighted k-nearest neighbor (WkNN)-based Fingerprinting positioning step, a process of comparing the requested positioning signal with signal information for each reference point stored in the fingerprint DB is performed. At this time, the higher the number of matched base station identifiers, the higher the possibility that the terminal exists in the corresponding location, and in fact, an additional weight is added to the location in proportion to the number of matching base stations. On the other hand, if the matching number of base stations is small, the selected candidate reference point has high dependence on the similarity value of the signal. But one problem arises here. The positioning signal can be compared with the repeater signal in the signal information stored on the DB, and the corresponding reference point can be selected as a candidate location. The selected reference point is likely to be an outlier, and if a certain weight is applied to the corresponding location, the error of the estimated location information increases. In order to solve this problem, this paper proposes a WkNN technique including an outlier removal function. To this end, it is first determined whether the repeater signal is included in the DB information of the matched base station. If the reference point for the repeater signal is selected as the candidate position, the reference position corresponding to the outlier is removed based on the clustering technique. The performance of the proposed technique is verified through data acquired in Seocho 1 and 2 dongs in Seoul.

• 한국기록관리학회지
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• 제21권1호
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• pp.211-230
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• 2021

이 연구는 민중가요가 장기·영구적으로 보존되고 이용될 수 있도록 OAIS 참조모형에 기반한 민중가요 메타데이터 설계를 하는 것이다, 이를 위해 문헌과 관련 기술표준 등을 조사하여 민중가요의 일반적 성격을 파악하고 민중가요 창작자와 연구자의 의견을 받아 기록물의 유형, 기록물의 장기보존 방법 및 표준, OAIS 참조모형과 각 패키지에 구성되는 메타데이터 요소를 확인하였다. 연구결과 1) 민중가요는 사회적 변혁을 위한 목적으로 창작되었고 비상업적 특성으로 상업성을 목적으로 하는 대중가요와의 차이점을 지니는 문화유산이다. 2) 민중가요 기록물의 유형을 확인하고 그 기록물의 유형에 부합하는 장기보 존체계는 OAIS 참조모형을 토대로 하였다. 3) 민중가요 기록물의 특성과 맥락성, 원질서를 존중하는 방안으로 메타데이터를 편집하여 OAIS 참조모형을 적용하였다. 4) 민중가요 기록물에 부합하는 정보패키지 메타데이터 요소를 도출하고, 이 요소들을 한국의 대표적인 민중가요인 '임을 위한 행진곡'에 적용하였다.

• Nutrition Research and Practice
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• 제17권1호
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• pp.135-148
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• 2023

BACKGROUND/OBJECTIVES: In times of disaster, simplified and minimized nutritional standards are necessary for a quick response to provide nutritious relief food. This study aimed to develop nutrient-based nutritional standards for foodservice at shelters during disasters in the Republic of Korea (South Korea). SUBJECTS/METHODS: The standards were developed in 2 phases. First, nutrients to be included in the standards were selected. Initial candidates were selected considering 3 aspects: preceding standards, insufficient intake during disasters, and inadequate intake among South Koreans. Final selection was made by excluding nutrients for 3 reasons: nutrients for which there is no deficiency concern in South Korea, nutrients whose intake data were not available, or nutrients whose values presented by Dietary Reference Intakes for Koreans are difficult to achieve based on the current diet among South Koreans. Second, the reference values of energy and the selected nutrients were calculated. The reference values for the entire population who were 1-year-old and over were calculated by multiplying the estimated energy requirements or the recommended nutrient intake and the proportion of each age and sex group. Respective reference values were also calculated for 4 different age groups (1-5, 6-11, 12-64, and ≥ 65-year-old). RESULTS: The standards for the entire population were 2,000 kcal for energy, 55 g for protein, 650 ㎍ retinol activity equivalents for vitamin A, 95 mg for vitamin C, 1.1 mg for thiamin, 1.3 mg for riboflavin, 14 mg niacin equivalents for niacin, 350 ㎍ dietary folate equivalents for folic acid, 750 mg for calcium, and 11 mg for iron. Four additional standards corresponding to each age group were developed. CONCLUSIONS: The nutritional standards during disasters were developed for South Korea, including energy and 9 nutrients with reference values for the entire population and 4 different age groups. The standards will contribute to maintaining the health of disaster evacuees in South Korea.

• Journal of Power Electronics
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• 제16권5호
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• pp.1964-1980
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• 2016

This paper presents a new simplified harmonics extraction algorithm based on the synchronous reference frame (SRF) for an indirect current controlled (ICC) three-level neutral point diode clamped (NPC) inverter-based shunt active power filter (SAPF). The shunt APF is widely accepted as one of the most effective current harmonics mitigation tools due to its superior adaptability in dynamic state conditions. In its controller, the SRF algorithm which is derived based on the direct-quadrature (DQ) theory has played a significant role as a harmonics extraction algorithm due to its simple implementation features. However, it suffers from significant delays due to its dependency on a numerical filter and unnecessary computation workloads. Moreover, the algorithm is mostly implemented for the direct current controlled (DCC) based SAPF which operates based on a non-sinusoidal reference current. This degrades the mitigation performances since the DCC based operation does not possess exact information on the actual source current which suffers from switching ripples problems. Therefore, three major improvements are introduced which include the development of a mathematical based fundamental component identifier to replace the numerical filter, the removal of redundant features, and the generation of a sinusoidal reference current. The proposed algorithm is developed and evaluated in MATLAB / Simulink. A laboratory prototype utilizing a TMS320F28335 digital signal processor (DSP) is also implemented to validate effectiveness of the proposed algorithm. Both simulation and experimental results are presented. They show significant improvements in terms of total harmonic distortion (THD) and dynamic response when compared to a conventional SRF algorithm.

• Journal of information and communication convergence engineering
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• 제14권4호
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• pp.207-214
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• 2016

In this paper, we propose a radial reference map-based location fingerprinting technique with constant spacing from an access point (AP) to all reference points by considering the minimum dynamic range of the received signal strength indicator (RSSI) obtained through an experiment conducted in an indoor environment. Because the minimum dynamic range, 12 dBm, of the RSSI appeared every 20 cm during the training stage, a cell spacing of 80 cm was applied. Furthermore, by considering the minimum dynamic range of an RSSI in the location estimation stage, when an RSSI exceeding the cumulative average by ${\pm}6dBm$ was received, a previously estimated location was provided. We also compared the location estimation accuracy of the proposed method with that of a conventional fingerprinting technique that uses a grid reference map, and found that the average location estimation accuracy of the conventional method was 21.8%, whereas that of the proposed technique was 90.9%.

• Bulletin of the Korean Chemical Society
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• 제30권1호
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• pp.133-136
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• 2009

A newly designed Ag/$Ag^+$ reference electrode in a quartz tube with a tungsten tip junction (W-tip-Quartz- REF) was fabricated and its electrochemical performance was compared with a conventional Pyrex tube-based Ag/$Ag^+$ reference electrode (Py-REF). The results of the electrochemical potential measurements with the W-tip-Quartz- REF and the Py-REF in the LiCl-KCl eutectic melts for a wide temperature range proved that the oxide layer on the surface of the tungsten metal tip provided a high ionic conduction. Stability of our newly designed W-tip- Quartz-REF was tested by measuring a junction potential for 12 hours at 700${^{\circ}C}$. The results of the cyclic voltammetric measurement indicated that the Ag/$Ag^+$ reference electrode in the quartz tube with a tungsten tip junction can provide a good performance for a wide temperature range.

• Smart Structures and Systems
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• 제12권2호
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• pp.181-207
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• 2013

In this paper, a statistical reference-free real-time damage detection methodology is proposed for detecting joint and member damage of truss bridge structures. For the statistical damage sensitive index (DSI), wavelet packet decomposition (WPD) in conjunction with the log likelihood ratio was suggested. A sensitivity test for selecting a wavelet packet that is most sensitive to damage level was conducted and determination of the level of decomposition was also described. Advantages of the proposed method for applications to real-time health monitoring systems were demonstrated by using the log likelihood ratios instead of likelihood ratios. A laboratory truss bridge structure instrumented with accelerometers and a shaker was used for experimental verification tests of the proposed methodology. The statistical reference-free real-time damage detection algorithm was successfully implemented and verified by detecting three damage types frequently observed in truss bridge structures - such as loss of bolts, loosening of bolts at multiple locations, sectional loss of members - without reference signals from pristine structure. The DSI based on WPD and the log likelihood ratio showed consistent and reliable results under different damage scenarios.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.102.5-102
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• 2002

In this paper auto-tuning scheme of PID controller based on the reference model has been studied by immune algorithm for a process. Up to this time, many sophisticated tuning algorithms have been tried in order to improve the PID controller performance under such difficult conditions. However, in the actual plant, they are manually tuned through a trial and error procedure, and the derivative action is switched off. Therefore, it is difficult to tune. Simulation results by immune based tuning reveal that tuning approaches suggested in this paper is an effective approach to search for optimal or near optimal process control.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.228-231
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• 1987

Microprocessor-based software DDA interpolator is developed and applied to two axis contouring control of X-Y table. Developed assembly program is composed of feedrate, linear and circular DDA interpolation routines. Reference-pulse type of open-loop stepping motor control system in which the micro-computer produces a sequence of reference pulses for each axis of motion is adopted. To test performance of the developed program, X-Y table drive system based on stepping motor and shaft encoder is designed. Contouring error of the system in linear and circular path is within .+-.0.2 mm.