• Journal of Nutrition and Health
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• v.31 no.8
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• pp.1347-1354
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• 1998

The purposes of this study were to : (a) anlayze wating time, service rate, arrival rate, and coustomer expectations/satisfaction in cafeteria business foodservices and (b) identify the differences in those factors between foodservices by menu managmenet systems. The samples were two business foodservices operated by contract management in Seoul. The queue, laptime , service rate, and arrival rate were measured at each foodservice by stopwatch observation. The menu type, delivery system, number of meals served , servide time, and turnover rate of each foodservic was investigated. Questionnaires were developed to survey customer expectations and satisfaction. Satistical data analysis was completed using the SAS package programs for descriptive analysis and t-test. The mean waiting time of island type dafeteria system with separte set -menu was shorter than that of the other. In both foodservices, arrival rates were not significantly different from one another , but sevice rates were significnatly high in dafeteria menu systems. The peak time of the queue was found out at combination set menu line. The separate set menu line had a higher servide rate than the combination set menu line. The mean waiting time of the island type cafeteria line was shorter than that of the straifth type . At the straight type dafeterial line, both arrival rate and service rate were higher than those of island-type. The results of this study suggested that a separate set-menu would be more desirable than a combination set-menu in case of providing set menu with cafeteria menu.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.46-53
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• 2015

Visible Light Communication (VLC) is effective way to realize the light device and communication device using a Light Emitting Diode (LED) simultaneously. VLC has high security for Field Of View (FOV) communication area, also which is possible to transmit the high data rate using visible light. In VLC, transmitting the divided data by the RGB channels is higher data rate than transmitting the same data by RGB channels. However, it occurred the burst error by scattering and reflection of visible light which is impossible to restore that. To solve the problem, we proposed the 2-step interleaving scheme that high data rate and improve the performance of BER in VLC. The proposed system implements cyclic interleaving and convolutional interleaving that is able to be standardized the performance of RGB channels and improve the performance of BER using error correction.

• ETRI Journal
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• v.37 no.3
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• pp.502-511
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• 2015

Intrusion detection plays a key role in detecting attacks over networks, and due to the increasing usage of Internet services, several security threats arise. Though an intrusion detection system (IDS) detects attacks efficiently, it also generates a large number of false alerts, which makes it difficult for a system administrator to identify attacks. This paper proposes automatic fuzzy rule generation combined with a Wiener filter to identify attacks. Further, to optimize the results, simplified swarm optimization is used. After training a large dataset, various fuzzy rules are generated automatically for testing, and a Wiener filter is used to filter out attacks that act as noisy data, which improves the accuracy of the detection. By combining automatic fuzzy rule generation with a Wiener filter, an IDS can handle intrusion detection more efficiently. Experimental results, which are based on collected live network data, are discussed and show that the proposed method provides a competitively high detection rate and a reduced false alarm rate in comparison with other existing machine learning techniques.

• Journal of Korean Society for Quality Management
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• v.42 no.1
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• pp.81-89
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• 2014

Purpose: The purpose of this study is to propose Clinical Practice Guideline(CPG) model and Clinical Index(CI) for implementing CDSS in digital hospitals. Methods: This study uses EMR data at department of family practice in A hospital; 636 patients, 570 diseases (based on ICD 10-CM criteria), and 37,000 data related with labs and treatments. This study focuses on disease J342 which is the most high rate of incidence. Results: Using the suggested model, this study calculates frequency matrix and probability matrix to find out the correlation of diseases and labs. This study indicates the lab sets of Disease (J342) as CI for CPG. Conclusion: This study suggests CPG model including Lab-based, Disease-Based and Case-based modules. Through 6 level cased-based CPG model, especially, this study develops Clinical Index(CI) such as the Incidence Rate, Lab Rate, Disease Lab Rate, Disease confirmed by Lab.

• Smart Structures and Systems
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• v.16 no.2
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• pp.295-328
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• 2015

In recent years the monitoring of structural behavior through acquisition of vibrational data has become common practice. In addition, recent advances in sensor development have made the collection of diverse dynamic information feasible. Other than the commonly collected acceleration information, Global Position System (GPS) receivers and non-contact, optical techniques have also allowed for the synchronous collection of highly accurate displacement data. The fusion of this heterogeneous information is crucial for the successful monitoring and control of structural systems especially when aiming at real-time estimation. This task is not a straightforward one as measurements are inevitably corrupted with some percentage of noise, often leading to imprecise estimation. Quite commonly, the presence of noise in acceleration signals results in drifting estimates of displacement states, as a result of numerical integration. In this study, a new approach based on a time domain identification method, namely the Unscented Kalman Filter (UKF), is proposed for correcting the "drift effect" in displacement or rotation estimates in an online manner, i.e., on the fly as data is attained. The method relies on the introduction of artificial white noise (WN) observations into the filter equations, which is shown to achieve an online correction of the drift issue, thus yielding highly accurate motion data. The proposed approach is demonstrated for two cases; firstly, the illustrative example of a single degree of freedom linear oscillator is examined, where availability of acceleration measurements is exclusively assumed. Secondly, a field inspired implementation is presented for the torsional identification of a tall tower structure, where acceleration measurements are obtained at a high sampling rate and non-collocated GPS displacement measurements are assumed available at a lower sampling rate. A multi-rate Kalman Filter is incorporated into the analysis in order to successfully fuse data sampled at different rates.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.561-563
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• 2005

From the IF (Intermediated Frequency) loop-back test, BER (Bit Error Rate) degradation of processed data, HRIT (High Rate Information Transmission), is estimated by proposed measurement configuration. The specific parameters, likely data rate, FEC (Forward Error Correction), and modulation method, are based on the outcomes of SRR (System Requirements Review) which was held on 13-14 June 2005, in Toulouse. The proposed measurement procedure is that combined 70MHz modulated signal and noise is connected to the spectrum analyzer and receiver. The former measures the C/No (Carrier to Noise density ratio) and the latter estimates BER of FEC decoded data. Implementation loss can be obtained by subtracting measured BER from calculated BER which is also subtracted data rate from measured C/No. This test procedure is very simple and can be applied to assess the implementation loss of dedicated receiver for HRIT in the future.

• Fire Science and Engineering
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• v.30 no.5
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• pp.87-92
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• 2016

Amid the growing number of high-rise complex buildings in Korea, efficient smoke prevention technology in a fire is required and as an alternative of a mechanical smoke control system in high-rise buildings, the use of a smoke control system using sandwich pressurization has been on the rise. In such a system, the appropriate pressure difference and the data for designing the air supply and exhaust flow rate are necessary to prevent the spread of smoke and offer a tenable evacuation environment. As part of such effort, this paper presents a field test process and result after testing a building where such a smoke control system using sandwich pressurization has been installed. A ventilation rate of 6 cycles per hour were applied to simulate the air exhaust flow rate on a fire floor and the air supply flow rate on the floors above and below the fire floor. As a result of the system operation, pressure difference of approximately 260 Pa between the 12th floor of a fire and the 13th floor was generated. The over pressure of the experiment has a serious effect on the evacuation or fire compartment so that it is necessary to examine the improvement.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.251-254
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• 2004

Hybrid rockets have many advantages over solid and liquid rockets. Hybrid rockets put forth high $I_{sp}$ like liquid rockets in spite of simple structure and low cost. As oxidizer flow rate is increased, thrust of hybrid rocket is increased accordingly. In this study, lab-scale hybrid rocket is designed, fabricated and tested. This system consists of lab-scale hybrid rocket motor, ignition system, flow system and data aquisition system. In order to control oxidizer flow rate, we construct flow rate control system by using needle valve and stepping motor.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.1
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• pp.34-41
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• 1998

In this paper, I designed a P1394 serial bus chip as new bus interface architecture which can transmit the multimedia data at the rate of 400 Mbps and guarantee necessary bandwidth. because multimedia data become meaningless data after appropriate time, it is necessary to transfer multimedia data in real time, P1394 serial bus chip designed in this paper support isochronous transfer mode to solve this problem. Also, designed P1394 serial bus chip can transfer high quality video data or high quality audio data because it support the speed of 400 Mbps. While user must set device ID manually in previous interface such as SCSI, device ID is automatically determined if user connect each node with designed P1394 serial bus cable and power on. To design this chip, I verified the behavioral of the entrire system and synthesized layout. Also, I did layout the analog blocks and blocks which must be optimized in full custom.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.1
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• pp.58-66
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• 2013

Most of steam power plant in Korea are heating the feed water system to prevent freezing water flowing in the pipe in winter time. The heating system is operated whenever the ambient temperature around the power plant area below 5 degree Centigrade. But this kind of heat supplying system cause a lot of energy consuming. If we think about the method that the temperature of the each pipe is controled by attaching the temperature measuring sensor like RTD sensor and heat is supplied only when the outer surface temperature of the pipe is under 5 degree Centigrade, then we can save a plenty of energy. In this study, the computer program package for simulation is used to compare the energy consumption load of both systems. Energy saving rate is calculated for the location of Youngweol area using the data of weather station in winter season, especially the January' severe weather data is analyzed for comparison. Various convection heat transfer coefficients for the ambient air and the flowing water inside the pipe was used for the accurate calculation. And also the various initial flowing water temperature was used for the system. Steady state analysis is done previously to approximate the result before the simulation. The result shows that the temperature control system using RTD sensor represents the high energy saving effect which is more than 90% of energy saving rate. Even in the severe January weather condition, the energy saving rate is almost 60%.