• Journal of Electrical Engineering and information Science
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• 제2권5호
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• pp.17-26
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• 1997

Interconnect characterization on a wafer level was performed. Test patterns for single, two-coupled, and triple-coupled lines ere designed by using 0.5$\mu\textrm{m}$ CMOS process. Then interconnect capacitances and resistances were experimentally extracted by using tow port network measurements, Particularly to eliminate parasitic effects, the Y-parameter de-embedding was performed with specially designed de-embedding patterns. Also, for the purpose of comparisons, capacitance matrices were calculated by using the existing CAD model and field-solver-based commercial simulator, METAL and MEDICI. This work experimentally verifies that existing CAD models or parameter extraction may have large deviation from real values. The signal transient simulation with the experimental data and other methodologies such as field-solver-based simulation and existing model was performed. as expected, the significantly affect on the signal delay and crosstalk. The signal delay due to interconnects dominates the sub-micron-based a gate delay (e.g., inverter). Particularly, coupling capacitance deviation is so large (about more than 45% in the worst case) that signal integrity cannot e guaranteed with the existing methodologies. The characterization methodologies of this paper can be very usefully employed for the signal integrity verification or he electrical design rule establishments of IC interconnects in the industry.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.491-494
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• 2006

Kalman filtering (KF) is hard to be applied to the SINS (Strap-down Inertial Navigation System)/RDSS (Radio Determination Satellite Service) integrated navigation system directly because the time delay of RDSS positioning in active mode is random. BP (Back-Propagation) Neuron computing as a powerful technology of Artificial Neural Network (ANN), is appropriate to solve nonlinear problems such as the random time delay of RDSS without prior knowledge about the mathematical process involved. The new algorithm betakes a BP neural network (BPNN) and velocity feedback to aid KF in order to overcome the time delay of RDSS positioning. Once the BP neural network was trained and converged, the new approach will work well for SINS/RDSS integrated navigation. Dynamic vehicle experiments were performed to evaluate the performance of the system. The experiment results demonstrate that the horizontal positioning accuracy of the new approach is 40.62 m (1 ${\sigma}$), which is better than velocity-feedback-based KF. The experimental results also show that the horizontal positioning error of the navigation system is almost linear to the positioning interval of RDSS within 5 minutes. The approach and its anti-jamming analysis will be helpful to the applications of SINS/RDSS integrated systems.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 춘계종합학술대회
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• pp.395-398
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• 2004

본 논문은 원격지의 데이터와 각종 디바이스들을 ON/OFF 하고, 상태를 웹 브라우져를 통하여 실시간으로 확인 할 수 있도록 하는 임베디드 시스템과 응용모듈 제작에 관한 논문이다. 최근 초고속 인터넷 발달과 인터넷 시설이 잘 갖추어진 특성 때문에 원격지의 각종 데이터와 디바이스 상태들을 직접 실시간으로 제어하고 검출할 수 있는 기술은 다방면으로 응용분야가 광범위하다고 생각된다.

• 인터넷정보학회논문지
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• 제24권2호
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• pp.1-10
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• 2023

The Multi-access Edge Computing (MEC) paradigm equips network edge telecommunication infrastructure with cloud computing resources. It seeks to transform the edge into an IT services platform for hosting resource-intensive and delay-stringent services for mobile users, thereby significantly enhancing perceived service quality of experience. However, erratic user mobility impedes seamless service continuity as well as satisfying delay-stringent service requirements, especially as users roam farther away from the serving MEC resource, which deteriorates quality of experience. This work proposes a deep reinforcement learning based service mobility management approach for ensuring seamless migration of service instances along user mobility. The proposed approach focuses on the problem of selecting the optimal MEC resource to host services for high mobility users, thereby reducing service migration rejection rate and enhancing service availability. Efficacy of the proposed approach is confirmed through simulation experiments, where results show that on average, the proposed scheme reduces service delay by 8%, task computing time by 36%, and migration rejection rate by more than 90%, when comparing to a baseline scheme.

• 한국음향학회지
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• 제27권8호
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• pp.427-434
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• 2008

본 논문에서는 SMV와 AMR 음성부호화기를 위한 상호부호화 알고리즘을 제안한다. 각기 다른 통신망에서 음성부호화기간의 효율적인 연동을 위해 가장 간단한 방법인 tandem 방식이 있지만 긴 지연시간과 많은 연산량, 그리고 음질 저하의 문제점들을 해결하기위해 상호부호화 방법을 사용한다. 제안하는 상호부호화 알고리즘은 LSP (Line Spectral Pairs) 변환, 피치 변환, 그리고 고속 고정 코드북 탐색을 수행한다. 실험 결과, $20\sim50%$의 적은 계산량과 $5\sim10$ ms의 지연 시간을 줄이면서도 동등한 음질을 확인할 수 있었다.

• 대한통합의학회지
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• 제10권4호
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• pp.11-21
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• 2022

Purpose : The purpose of this study is to identify the degree of occupational therapist's professional ethics and to examine the correlation between professional ethics, job stress, and burnout. It also investigates the effects of the occupational therapist's professional ethics on job stress, and burn out, so that we can find a way to reduce them in occupational therapists. Methods : We conducted surveys from June 1 to July 5, 2022. The general characteristics were examined using a frequency analysis. Professional ethics, job stress, and burn out were examined using descriptive statistics. The correlation among them was analyzed with the Pearson correlation coefficient. To find out what factors affect job stress and burn out, we also conducted a multiple regression analysis. Results : First, professional ethics was averaged at 3.57±.34. Second, a significant negative correlation in professional ethics was found between job stress and burn out (p<.01). As a result of the correlation between occupational ethics sub-factors and job stress and burnout, factors excluding nonleisure and self-reliance showed a statistically significant correlation (p<.01, p<.05). Third, professional ethics sub-factor was affected job stress and burn out (p<.01, p<.05). The sub-factors affecting job stress were hard work (𝛽=.-461, p<.01), delay of gratification (𝛽=.-267, p<.01), and relation with coworker (𝛽=.-245, p<.01) and morality (𝛽=.-165, p<.05); and those influencing burnout were delay of gratification (𝛽=-.240, p<.01), relation with coworker (𝛽=-.223, p<.01), centrality of work (𝛽=-.189, p<.01) and hard work (𝛽=-.184, p<.05). Conclusion : The results of this study confirmed the importance of professional ethics affecting job stress and burn out. Through follow-up research, it will be necessary to develop and apply programs to improve professional ethic of occupational therapists in the future.

• Journal of Nutrition and Health
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• 제30권6호
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• pp.690-703
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• 1997

The purpose of this study were to analyze work function and labor productivity in school foodservice systems through work sampling methodology. Conventional foodservice were classified into 5 group depending on the number of meals served. Commissary school foodservices were also classified into 5 group by cluster analysis using the number of meals served, the number of satellite schools, and the duration of time for delivery of food. Work measurement through work sampling methodology was conducted in at 5 conventional and 21 commissary food -services during 3 consecutive days from September to October in 1995. Results from work measurement through work sampling methodology were as followed : The most prevalent work functions was cleaning (26.5%) and then processing (25.1%) in conventional while it was processing (30.9%) and then cleaning(25.2%) in commissary school foodservice. Delay was 22.9% and 19.7% respectively. Mean labor minutes per meal of conventional and commissary foodservics were 4.57 and 4.09 minutes, respectively : no significant difference in labor minutes per meal existed between the two systems. but mean labor minutes per meal of commissary foodsevices(1.79min) was significantly lower than that of conventional foodservice(2.33min) during work time before service (p<0.05). Productivity was significantly lower in foodservices which served less than 400 servings ; n significant differences existed among 401-70, 701-1,100 and 1,101-1,500 meals. The highest productivity was in conventional school foodservices which served 1,501-1,900meals. Labor minutes per meal of commissary school foodservice which served less than 400meals per day was significantly lower than those of foodservice which served 401-1,900meals (p<0.05). Labor minutes per meal, preparation and cleaning were positively correlation in two school foodservice systems.

• 한국음향학회지
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• 제16권5호
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• pp.96-104
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• 1997

본 논문에서는 임펄스 잡음이 부가되는 환경 하에서 시지연 추정 및 시지연과 주파수 지연 목합 추정을 위한 새로운 강건 알고리즘들을 제안하였다. 제안된 방법은 ${\alpha}-stable$ 분포 이론을 바탕으로 하여 음의 분수 차수 모멘트(FNOM: fractional negative order moment)와 최소 산란(MD : minimum dispersion) 법을 이용한 강건 시지연 추정법들과 이를 응용한 시지연과 주파수 지연의 복합 추정법인 음의 분수 차수 모호함수법과 복합 최소 산란 법으로 구성되었다. 제안한 방법들을 평가하기 위하여 컴퓨터 모의 실험을 통해서 실제 응용 능력을 기존의 여러 방법들과 비교. 검토하였다. 실험 결과 2차 모멘트 이론을 바탕으로 한 관례적인 방법들은 가우시안 잡음 환경 (${\alpha}$=2인 $S{\alpha}S$ 잡음) 하에서만 시지연 추정이 가능하였고, 최근 제안된 Nikias[7]의 강건 시지연 추정법 들도 대부분이 제한된 임펄스 잡음 ($1<{\alpha}{\le}2$인 $S{\alpha}S$ 잡음)에 대해서만 그 성능이 입증된 반면, 본 연구에서 제안한 방법들은 가우시안 잡음 및 심한 임펄스 잡음 ($0<{\alpha}{\le}2$인 $S{\alpha}S$ 잡음) 하에서도 강건하게 시지연 추정이 가능함을 입증하였다.

• 정보보호학회논문지
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• 제33권5호
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• pp.787-799
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• 2023

가정에서 IoT 장비가 많이 활용되면서, IoT 장비를 통합하여 사용자의 편의에 맞게 사용하는 IoT automation system을 향한 관심도 많아졌다. IoT automation system에서는 사전 정의된 자동화규칙에 따라 IoT 장비의 정보를 수집하고, IoT 장비가 작동한다. 하지만 공격자는 패킷을 지연시켜 실제 상태와 시스템에서 인식한 상태의 불일치가 되는 시간을 만든다. 이 시간 동안 시스템은 사전 정의한 자동화 규칙대로 동작하지 않는다. 제안된 지연공격 탐지방법이 일부 있지만, 트래픽량이나 배터리에 민감한 IoT system에 적용하기에 제한사항이 있다. 본 논문에서는 IoT 시스템에 적용할 수 있는 실용적인 패킷 지연 공격 탐지 방법을 제시한다. 제안 방법은 메시지를 전송할 때, 메세지의 전송을 알리는 패킷을 브로드캐스트로 발송함으로써 서버가 이벤트의 발생을 인지할 수 있도록 한다. 평가를 위하여 Raberry pi로 구현된 IoT system을 구성하고, 패킷 지연 공격에 대하여 평균2.2초이내로탐지할 수 있음을 보였다. 실험 결과 소모 전류 Overhead는 초당 평균 2.5 mA, 트래픽 Overhead는 15% 발생하였고, 기존 제안된 탐지방법보다 효율적으로 Delay attack을 탐지할 수 있음을 밝혔다.

• 한국통신학회논문지
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• 제21권1호
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• pp.241-250
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• 1996

In this work, an improved architecture of two-dimensional digital filter(2D DF) is suggested, and then the filter is simulated by C, VHDL language and related layouts are designed by Berkeley CAD tools. The 2D DF consists of one-dimensional digital filters and delay lines. For one-dimensional digital filter(1D DF) case, once filter coefficients are represented by canonical signed digit formats, multiplications are exected by hardwired-shifting methods. The related bit numbers are handled to prevent picture quality degradation and pipelined adder architectures are adopted in each tap and output stage to speed up the filter. For delay line case, line-sharing DRAM is adopted to improve power dissipation and speed. The filter layout is designed by semi/full custom methods considering regularity and speed improvement, and normal operation is confirmed by simulation.