• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.326-329
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• 2004

In this paper, we show a new form of blood pressure controller combined PI control with $H_{\infty}$ loop-shaping. Hypertensive patients or post-operative patients need to maintain normally blood pressure. Exact regulation of blood pressure is needed for maintaining variable blood pressure of preventing complications. The regulation of blood pressure is achieved by injecting drugs, and usually sodium nitroprusside is used as those kinds of drugs. It is necessary to control the infusion rate sodium-nitroprusside carefully to achieve the desired blood pressure. It has been known that regulation of blood pressure by automatic controller is more effective than regulation of blood pressure by human operators. The control of blood pressure has many constraints and uncertainties. Most of biological system has the time-varying variables and the side effects such as increased risk of sepsis and organ failure. To solve such a problem, we design a new robust PI controller using $H_{\infty}$ loop-shaping to decrease noise effects that come out from human body and errors for time delay. The system with designed controller shows more stable control of mean blood pressure and more robust performance for uncertainties. Validation methods for the control performance are confirmed to computer simulations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.737-742
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• 2007

The method of the reducing duct noise can be classified by passive and active control techniques. However, passive control has a limited effect of noise reduction at low frequencies (below 500Hz) and is limited by the space. On the other hand, active control can overcome these passive control limitations. The active control technique mostly uses the Least-Mean-Square (LMS) algorithm, because the LMS algorithm can easily obtain the complex transfer function in real-time particularly when the Filtered-X LMS (FXLMS) algorithm is applied to an active noise control (ANC) system. However, the convergence performance of the LMS algorithm decreases slightly so it may delay the convergence time when the FXLMS algorithm is applied to the active control of duct noise. Thus the Co-FXLMS algorithm was developed to improve the control performance in order to solve this problem. The Co-FXLMS algorithm is realized by using an estimate of the cross correlation between the adaptation error and the filtered input signal to control the step size. In this paper, the performance of the Co-FXLMS algorithm is presented in comparison with the FXLMS algorithm. Simulation results show that active noise control using Co-FXLMS is effective in reducing duct noise.

• Journal of applied mathematics & informatics
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• v.26 no.5_6
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• pp.1149-1159
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• 2008

Blind source extraction (BSE) is a special class of blind source separation (BSS) methods, which only extracts one or a subset of the sources at a time. Based on the time delay of the desired signal, a simple but important extraction algorithm (simplified " BC algorithm")was presented by Barros and Cichocki. However, the performance of this method is not satisfying in some cases for which it only carries out the constrained minimization of the mean squared error. To overcome these drawbacks, ICA with reference (ICA-R) based approach, which considers the higher-order statistics of sources, is added as the second stage for further source extraction. Specifically, BC algorithm is exploited to roughly extract the desired signal. Then the extracted signal in the first stage, as the reference signal of ICA-R method, is further used to extract the desired sources as cleanly as possible. Simulations on synthetic data and real-world data show its validity and usefulness.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.69-74
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• 2003

GPS/Meteorology technique for PWV monitoring is currently actively being researched an advanced nation. But, there is no detailed research on an evaluation of precision of GPS derived PWV measurements during the period of foul weather condition. Here, we deal with the precision of GPS derived PWV during the passage of Typhoon RUSA. Typhoon RUSA which caused a series damage was passed over in Korea from August 30 to September 1, 2002. We compared th tropospheric wet delay estimated from GPS observation and radio-sonde data at four sites(Suwon, Kwangju, Taegu, Cheju). The mean standard deviation of PWV differences at each site is ${\pm}$0.005mm. We also obtained GPS PWV at 13 GPS permanent stations(Seoul, Wonju, Seosan, Sangju, Junju, Cheongju, Taegu, Wuljin, Jinju, Daejeon, Mokpo, Sokcho, Jeju). GPS PWV time series shows, in general, peak value before and during th passage of RUSA, and low after the RUSA. GPS PWV peak time at each station is related to the progress of a typhoon RUSA. We obtained very similar result as we compare GMS satellite image with tomograph using GPS PWV and we could present th possibility of practical use by numerical model for weather forecast.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.6
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• pp.1510-1521
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• 1996

This paper presents acquisition algorithm and an improved detection technique for the DS/CDMA (direction sequence code division multiple access) RAKE receiver in multipath fading channel. The DS/CDMA systems use the RAKE receiver, an accurate code acquisition is required for the RAKE branches. The algorithmis able to findthe pseudonoise (PN) code delay estimates for the RAKE branches in a multipath fading channel. In this paper a numerical method and computer simulation simulation have been developed for the acquisition system. The detection probability and mean acquisition time are investigated asa performance measure of the system using the Monte Carlo method. And also in order to analyze the effect of the acquisition on the RAKE receiver this paper bring out the effect of integration time, doppler frequency, processing gain and the number of users on the acquired code phase.

• International Journal of Automotive Technology
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• v.7 no.3
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• pp.345-351
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• 2006

Software-In-the-Loop Simulation(SILS) and Rapid Control Prototyping(RCP) are proposed as an integrated development environment to support the development process from system design to implementation. SILS is an environment used to simulate control systems with temporal behavior. RCP offers seamless phase shift from design to implementation based on automatic code generation. There are several toolsets that support control system design and analysis. A few of these tools generate the control software automatically. However, most of these design toolsets do not cover temporal behavior which appears after implementation. In earlier toolsets, the design and the implementation of a control system are considered as two separate processes which mean the conventional development process is not connected strictly. SILS/RCP environments work under an identical platform and use the same representation for system modeling. An integrated SILS/RCP environment makes it possible to design controllers under conditions similar to real execution during off-line simulation and to realize controllers in the early design phase. SILS/RCP environments integrate the design and implementation phases which reduce the time-to-market and provide greater performance-assured design. The establishment of SILS/RCP and the practical design approaches are presented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.2
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• pp.253-260
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• 2018

The acoustic communication channel in shallow underwater is typically shown as time-varying multipath fading channel characteristics. The received signal through channel transmission cause inter-symbol interference (ISI) owing to multiple components of different time delay and amplitude. To compensate for this, several techniques have been used, and one of them is acoustic equalizer. In this study, we used four equalizers - feed forward equalizer (FFE), decision directed equalizer (DDE), decision feedback equalizer (DFE) and combination DDE with DFE to compensate ISI. And we applied two adaptive algorithms to adjust coefficient of equalizers - normalized least mean square algorithm and recursive least square algorithm. As result, we found that it has a significant performance improvement over 6 dB on SNR in nonlinear equalizer. By combination of DFE and DDE has almost best performance in any case.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2515-2518
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• 2012

Aim: To study the causes and significance of both microscopic and macroscopic haematuria in adult patients and assess possible relevance to early detection of urological cancers. Methods: 417 patients presenting with haematuria were assessed in our Urology Unit. Following confirmation of haematuria, these patients were subjected to imaging techniques and flexible cystoscopy. Parameters analysed included clinical characteristics, imaging results, flexible cystoscopy findings, time delay to diagnoses and eventual treatment and final diagnoses of all cases. Results: 390 haematuria cases were analysed from 417 consecutive patients with haematuria. After 27 cases were excluded as they had previous history, 245 microscopic and 145 macroscopic. Age range was 17 to 95 years old with predominance of 152 females to 239 males. The racial distribution included 180 Chinese, 100 Indians,95 Malays and 15 other races. The final diagnoses were benign prostatic hyperplasia (22.6%), no cause found (22.3%), other causes (18.7%), urolithiasis (11.5%), urinary tract infection UTI (10.8%), non specific cystitis (10.3%), bladder tumours (2.8%) and other genitourinary tumours (1%). 11 new cases (2.8%) of bladder cancers were diagnosed, with a mean age of 59 years. Only 3 of 245 (1.2%) patients with microscopic haematuria had newly diagnosed bladder tumour compared with 8 of 145 (5.5%) patients with frank haematuria (p=0.016). Mean time taken from onset of symptoms to diagnosis of bladder cancer was 53.3 days with definitive treatment (TURBT) in 20.1 days from diagnosis. Conclusion:- This study has highlighted the common causes of haematuria in our local setting. We recommend that full and appropriate investigations be carried out on patients with frank haematuria especially those above 50 years old in order to provide earlier detection and prompt management of bladder diseases especially tumours.

• Journal of Nutrition and Health
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• v.30 no.6
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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.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.183-191
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• 2010

In the recent digital communication systems, the performance of Turbo Code used as the error correction coding method depends on the interleaver size influencing the free distance determination and the iterative decoding algorithms of the turbo decoder. However, some iterations are needed to get a better performance, but these processes require a large time delay. Recently methods of reducing the number of iteration have been studied without degrading original performance. In this paper, the new method of combining ME (Mean Estimate) stopping criterion with SDR (sign difference ratio) stopping criterion among previous stopping criteria is proposed, and the fact of compensating each method's missed detection is verified. Faster decoding is realized that about 1~2 time iterations to reduced through adopting this method into serially concatenated both decoders. System Environments were assumed W-CDMA forward link system with intense MAI (multiple access interference).