• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제6권1호
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• pp.36-44
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• 2000

본 논문은 고속통신망을 통하여 사용자 개입을 허용하는 멀티미디어 프리젠테이션과 멀티미디어 응용에 포함된 다양한 미디어의 저작을 동시에 수행할 수 있는 도구의 개발에 관한 것이다. 도구 개발을 위해 실시간 동기식 멀티미디어 프리젠테이션을 지원하기 위해 동적 버퍼링 기법, 송수신 시스템간의 데이타 전송률을 동기화를 위해 버퍼 관리 기법과 QoS 파라메터를 기반으로 한 적응형 전송 알고리즘을 적용하였다. 또한, TRSG 모델을 이용하여 사용자가 프리젠테이션 도중에 참여할 수 있도록 하였다. 마지막으로 제안된 도구가 QoS 유지 및 동기화에 영향을 미치는 요소들을 계속적으로 모니터링하여 멀티미디어 프리젠테이션의 수행 상태를 지속적으로 제어하는 이벤트 감시 스레드 기법을 적용하여 연속적인 출력보장과 최소한의 QoS를 지원할 수 있도록 하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권8호
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• pp.4227-4240
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• 2019

In this paper, we present our proposed magnetic induction based wireless communication system. The proposed system is designed to perform communication as well as distance measurement in underground environments. In order to improve the communication quality, we propose and implement the adaptive channel compensation technique. Based on the fact that the channel may be fast time-varying, we keep track of the channel status each time the data is received and accordingly compensate the channel coefficient for any change in the channel status. By using the proposed compensation technique, the developed platform can reliably communicate over distances of 10m while the packet error rate is being maintained under 5%. We also implement the distance measurement block that is useful for various applications that should promptly estimate the location of nearby nodes in communication. The distance between two nodes in communication is estimated by generating a table describing pairs of the magnetic signal strength and the corresponding distance. The experiment result shows that the platform can estimate the distance of a node located within 10m range with the measurement error less than 50cm.

• 한국컴퓨터정보학회논문지
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• 제23권11호
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• pp.51-57
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• 2018

In this paper, we studied about the extraction of the parameter and implementation of speechreading system to recognize the Korean 8 vowel. Face features are detected by amplifying, reducing the image value and making a comparison between the image value which is represented for various value in various color space. The eyes position, the nose position, the inner boundary of lip, the outer boundary of upper lip and the outer line of the tooth is found to the feature and using the analysis the area of inner lip, the hight and width of inner lip, the outer line length of the tooth rate about a inner mouth area and the distance between the nose and outer boundary of upper lip are used for the parameter. 2400 data are gathered and analyzed. Based on this analysis, the neural net is constructed and the recognition experiments are performed. In the experiment, 5 normal persons were sampled. The observational error between samples was corrected using normalization method. The experiment show very encouraging result about the usefulness of the parameter.

• 한국응급구조학회지
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• 제24권3호
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• pp.89-106
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• 2020

Purpose: This study attempts to improve the status of emergency care for major trauma patients transferred by 119 paramedics by analyzing the status of emergency care and the obstacles to the spinal motion restriction (SMR) for major trauma patients. Methods: A total of 600 rescue logs were collected from major trauma patients transported by 119 paramedics in the C fire department from Jan. 1, 2015, to Dec. 31, 2017. And then, 280 questionnaires were collected from the 119 paramedics in C fire department from May 3 to Jun. 3, 2019. Data were analyzed using SPSS 24.0 version. Results: Among 499 spinal motion restriction adaptive patients, the spinal motion restriction rate was 51.1% (255 individuals). Lack of human resources and quality control problems were among the obstacles to spinal motion restriction. Conclusion: The 119 paramedics should improve their activeness and skills in performing emergency care, and since training and experience are of crucial importance, they should expand various education systematized according to demand.

• The Journal of Asian Finance, Economics and Business
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• 제8권2호
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• pp.65-75
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• 2021

This study analyzes the validity of the Phillips curve with regards to Turkey. The existence and direction of the causality relationship (reason-outcome relationship) between unemployment and inflation is investigated using inflation and unemployment data for the period 1980-2019. Unit root tests were utilized to evaluate the stationarity of the series. In line with the Zivot-Andrews unit root test, which was developed in response to the criticism of the failure of studies that presented macro-variables like inflation to consider traditional unit root tests, in this research, the Engle-Granger cointegration test was implemented to check whether the series could perform a joint action, and, finally, the Granger causality relationship was explored. According to the results of the analysis, over the relevant period there was a single directional causality relationship from inflation toward unemployment in Turkey. The importance of this relationship at the 10% significance level indicates the existence of many different factors that affect inflation and unemployment. Given the existence of a cointegration and causality relationship between inflation and unemployment, it can be said that, in Turkey, the Phillips curve is valid for the period 1980-2019 and that an increase of 1% in inflation will reduce the unemployment rate by 0.028%.

• 대한건축학회논문집:구조계
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• 제35권9호
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• pp.207-214
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• 2019

Natural ventilation through openings such as windows in school buildings is an efficient resource for natural cooling during the intermediate season of the year. Because the natural ventilation uses the wind outside the building, the amount of ventilation will depend not only on the wind speed and wind direction but also on the window layout and open window ratio. Therefore, in this study, the natural ventilation plans of school classroom windows are divided into 4 types and 8 cases as shown in Table 1. The characteristics of cooling effect by natural ventilation are simulated by applying Energyplus's Airflow Network Model and the comfort of the occupants is evaluated by the number of hours included in the 80% acceptability range of the ASHRAE Standard 55-2010 adaptive comfort model for the weekdays (Monday-Friday) and the class hours (08: 00-19: 00). Based on the analysis results of the above, this study presents basic data related to classroom cooling plan using intermediate season natural ventilation.

• Nuclear Engineering and Technology
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• 제54권5호
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• pp.1712-1725
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• 2022

For improving the seismic performance of the nuclear power plant (NPP) piping system, attempts have been made to apply a dynamic absorber (DA). However, the current piping DA design method is limited because it cannot provide the globally optimum values for the target design seismic loading. Therefore, this study proposes a seismic time history analysis-based DA optimal design method for piping. To this end, the Kriging approach is introduced to reduce the numerical cost required for seismic time history analyses. The appropriate design of the experiment method is used to increase the efficiency in securing response data. A gradient-based method is used to efficiently deal with the multi-dimensional unconstrained optimization problem of the DA optimal design. As a result, the proposed method showed an excellent response reduction effect in several responses compared to other optimal design methods. The proposed method showed that the average response reduction rate was about 9% less at the maximum acceleration, about 5% less at the maximum value of the response spectrum, about 9% less at the maximum relative displacement, and about 4% less at the maximum combined stress compared to existing optimal design methods. Therefore, the proposed method enables an effective optimal DA design method for mitigating seismic response in NPP piping in the future.

• Current Optics and Photonics
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• 제7권4호
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• pp.345-353
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• 2023

We propose a turbulence-tolerant Manchester on-off keying (M-OOK) transmission for free-space optical (FSO) communication. At the transmitter end, a M-OOK signal featuring a spectrum with low-frequency components absent is modulated and transmitted into a turbulent channel. At the receiver end, a low-pass filter (LPF) -based adaptive-threshold decision (ATD) with LPF-extracted channel-state information (CSI) and a high-pass filter (HPF)-based fixed-threshold decision (FTD) are employed to compensate for the effects of turbulence, owing to the low-frequency spectral characteristics of the turbulent channel. The performance of LPF-based ATD and HPF-based FTD are evaluated for various cutoff frequencies for the LPF and HPF. Besides, the proposed M-OOK transmission is compared to conventional non-return-to-zero OOK (NRZ-OOK) for different data rates. The proposed technique is verified in simulation. The simulation results show that the proposed M-OOK detection with optimized cutoff frequencies of LPF and HPF has better bit-error-rate (BER) performance compared to NRZ-OOK, and it is close to the theoretical ATD with the knowledge of precise CSI under various degrees of turbulence effects.

• 한국전기전자재료학회논문지
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• 제20권1호
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• pp.57-64
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• 2007

One of the cause of insulation failure in power cable is well known by electrical treeing discharge. This is occurred for imposed continuous stress at cable. And this event is related to safety, reliability and maintenance. In this paper, throughout analysis of partial discharge(PD) distribution when occurring the electrical tree, is studied for the purpose of knowing of electrical treeing discharge characteristics according to defects. Own characteristic of tree will be differently processed in each defect and this reason is the first purpose of this paper. To acquire PD data, three defective tree models were made. And their own data is shown by the phase-resolved partial discharge method (PRPD). As a result of PRPD, tree discharge sources have their own characteristics. And if other defects (void, metal particle) exist internal power cable then their characteristics are shown very different. This result Is related to the time of breakdown and this is importance of cable diagnosis. And classification method of PD sources was studied in this paper. It needs select the most useful method to apply PD data classification one of the proposed method. To meet the requirement, we select methods of different type. That is, neural network(NN-BP), adaptive neuro-fuzzy inference system and PCA-LDA were applied to result. As a result of, ANFIS shows the highest rate which value is 98 %. Generally, PCA-LDA and ANFIS are better than BP. Finally, we performed classification of tree progress using ANFIS and that result is 92 %.

• 전자공학회논문지
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• 제51권5호
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• pp.51-57
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• 2014

본 논문에서는 M-ary 홀로그래픽 데이터 저장장치에 적용 가능한 진화 연산 알고리즘 기반 적응적 문턱치 검출 기법을 제안한다. 전통적으로 유전 알고리즘은 생명체의 유전자 진화과정에 근간하여 최적 혹은 준최적 문제와 데이터 추정을 위해 사용되는 매우 유용한 기법이다. 본 연구에서는 픽셀 어긋남이 심화되는 2차원 홀로그래픽 채널 환경에서 데이터의 검출 성능을 향상시키기 위해서, 각 데이터 검출 영역의 문턱 값(threshold value)을 유전 알고리즘의 인구 집합(population set)의 해로 간주하여 비트 검출 영역을 적응적으로 선택하는 방법을 제안한다. 제안하는 기법의 성능을 평가하기 위해 픽셀 어긋남 현상이 심화된 4-ary 멀티레벨 입력의 홀로그래픽 채널 환경을 고려하고 모의실험을 수행하여 진화 연산의 세대수에 따른 비트오율 성능을 측정한다. 성능평가를 통해 기존의 비트 검출 기법과 비교함으로써 제안 기법의 우수성을 확인하였다.