• 설비공학논문집
• /
• 제2권2호
• /
• pp.85-98
• /
• 1990

Method of optimum design of a compact sensible plate-fin heat exchanger for the heat recovery of exhaust gas from the air conditioning space was developed in consideration of the econamics of investment cost and profit according to the installation of heat exchanges. In the counterflow heat exchanger, the frontal area was fixed and the length of heat exchanger was optimized in order to maximize the net gain according to the setting of the heat exchanger. In the cross flow heat exchanger, the size of the exchanger was also optimized to maximize the net gain.

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2001년도 춘계학술대회 논문집
• /
• pp.166-171
• /
• 2001

A digital seismic data acquisition and processing system using a PC has been developed in order to replace the analog data acquisition system of shallow marine seismic survey. An A/D converter that has 12bits of resolution and 225KHz of conversion rate was ued to acquire data, and a data acquisition software was developed as a Windows program which provides convenience of use. Raw data acquired at field has been saved to the hard-disk simultaneously. The signal to noise ratio, vertical and horizontal resolution could be improved by a digital data processing of the raw data. The digital processing of the raw data includss gain recovery, filtering, deconvolution, and muting. With the prediction deconvolution algorithm multiple reflections appearing on the shallow marine seismic section could be removed successfully.

• 한국정보통신학회논문지
• /
• 제10권7호
• /
• pp.1214-1221
• /
• 2006

헤더 압축 기술은 기존의 일반적인 패킷 데이터의 비효율적인 오버 헤드를 줄이기 위한 방안으로 제안되었다. 특히 음성과 같은 실시간 미디어 스트림 경우에는 더욱 큰 오버헤드율을 보이게 되는데, 헤더 압축을 통해 보다 높은 대역폭 효율을 얻을 수 있다. 본 논문에서는 PHR(periodic Header Refresh) 방법과 HR(Header Request) 방법 의 두가지 에러 복구 기법 에 관하여 각각 성능 분석을 실시하였다. 그 결과로 Overhead Rate, Bandwidth Gain, 그리고 Bandwidth Efficiency 등의 분석 결과가 제시되었다.

• Journal of Audiology & Otology
• /
• 제23권1호
• /
• pp.33-38
• /
• 2019

Background and Objectives: Determination of the lesion side based on the direction of the nystagmus could result in confusions to the clinicians due to mismatch between the vestibular function tests and also between vestibular and audiologic features. To minimize these mistakes, we elucidated the clinical manifestation and vestibular function test results in cases with recovery spontaneous nystagmus (rSN). Subjects and Methods: Patients who visited ENT clinic of tertiary referral hospital for acute onset continuous vertigo from January 2008 to December 2011 were enrolled. In these patients, we assessed onset time of vertigo, time point of paralytic spontaneous nystagmus (SN) and time point of rSN. At each time point of SN, vestibular function tests and hearing function tests were performed. Results: We confirmed the rSN among patients with unilateral vestibulopathy and demonstrated that high gain of the rotatory chair test (slow harmonic acceleration) and/or mismatch of the SN direction and contralateral caloric weakness could indicate the recovery state of patients and nystagmus observed in this stage is recovery phase nystagmus. Conclusions: In acute vestibulopathy patients, recovery phase nystagmus was observed and on this stage of disease vestibular function tests shows several features that could predict recovery state.

• 대한청각학회지
• /
• 제23권1호
• /
• pp.33-38
• /
• 2019

Background and Objectives: Determination of the lesion side based on the direction of the nystagmus could result in confusions to the clinicians due to mismatch between the vestibular function tests and also between vestibular and audiologic features. To minimize these mistakes, we elucidated the clinical manifestation and vestibular function test results in cases with recovery spontaneous nystagmus (rSN). Subjects and Methods: Patients who visited ENT clinic of tertiary referral hospital for acute onset continuous vertigo from January 2008 to December 2011 were enrolled. In these patients, we assessed onset time of vertigo, time point of paralytic spontaneous nystagmus (SN) and time point of rSN. At each time point of SN, vestibular function tests and hearing function tests were performed. Results: We confirmed the rSN among patients with unilateral vestibulopathy and demonstrated that high gain of the rotatory chair test (slow harmonic acceleration) and/or mismatch of the SN direction and contralateral caloric weakness could indicate the recovery state of patients and nystagmus observed in this stage is recovery phase nystagmus. Conclusions: In acute vestibulopathy patients, recovery phase nystagmus was observed and on this stage of disease vestibular function tests shows several features that could predict recovery state.

• ETRI Journal
• /
• 제30권4호
• /
• pp.606-608
• /
• 2008

MPEG Surround has a potential clipping problem since its encoding is based on downmixing a multichannel signal. We propose a clipping prevention scheme for MPEG Surround, which is composed of modification and recovery processes of a downmix signal with recovery information conveyed in arbitrary downmix gains of an MPEG Surround bitstream. Experiments show that the proposed scheme effectively prevents sound quality degradation caused by clipping problems with negligible additional bit rates.

• Journal of information and communication convergence engineering
• /
• 제14권2호
• /
• pp.106-114
• /
• 2016

Differential sensing methods are more effective in alleviating panel noise than single-line sensing, and thus have been increasingly used in the touch screen industry. However, they have a drawback: they tend to cancel out multiple touches and need touch position recovery algorithms. This paper introduces a novel algorithm of touch position recovery for differential sensing, which is a low-complexity but high-accuracy approach for determining multiple touch positions. We have implemented the proposed method in a touch screen controller system on a chip. In the simulation experiments using realistic touch screen models and a differential sensing circuit, the algorithm exhibited a high detection performance of a signal-to-noise ratio gain of up to 52.21 dB. Therefore, we can conclude that the proposed method is substantially more accurate than the previous method. Further, the proposed method incurs little or no overhead in terms of the detection speed and the chip size.

• Journal of the Optical Society of Korea
• /
• 제11권4호
• /
• pp.153-157
• /
• 2007

We have proposed an application of disturbance observer with PID controller to minimize gain-transient time of wavelength-division-multiplexing(WDM) multi channels in optical amplifier in channel add/drop networks. We have dramatically reduced the gain-transient time to less than $3{\mu}sec$ by applying a disturbance observer with a proportional/integral/ differential(PID) controller to the control of amplifier gain. The theoretical analysis on the 3-level erbium-doped fiber laser and the disturbance observer technique is demonstrated by performing the simulation with co-simulation of the $MATLAB^{TM}$ and a numerical modeling software package such as the $Optsim^{TM}$.

• 한국통신학회논문지
• /
• 제35권12C호
• /
• pp.1029-1034
• /
• 2010

QPSK 디지털 수신기는 전송 경로 또는 송수신기 간의 클럭 차이에 의해 발생하는 위상 편차를 보정하기 위해 위상 복원 방안이 필요하다. 널리 사용되고 있는 디지털 Costas 위상 복원 루프는 입력신호의 주파수/위상 복원 성능이 입력 신호의 전력에 따라 달라지므로 별도의 자동 이득조정 (AGC) 루프가 필요하고, 이는 하드웨어 구현시 시스템의 복잡도와 사용 자원을 증가시킨다. 본 논문에서는 입력 전력에 관계없이 일정한 위상 보정 기능을 수행할 수 있으며 타이밍 복원을 위한 AGC를 동시에 제공할 수 있는 위상 보정 및 진폭 보상 방안을 제안하였다. 제안된 방안은 CORDIC 알고리즘을 사용하여 입력 신호의 위상 및 진폭 정보를 분리하여 각각 처리하며 시스템의 복장도 및 사용 자원을 대폭 절감할 수 있으며, C++ 및 Model Sim을 사용한 모의실험을 통해 본 논문에서 제안한 위상 복원 루프의 동작을 검증하였다.

• Nutrition Research and Practice
• /
• 제9권3호
• /
• pp.268-277
• /
• 2015

BACKGROUND/OBJECTIVES: Although it is crucial to identify those children likely to be treated in an appropriate nutrition rehabilitation programme and discharge them at the appropriate time, there is no golden standard for such identification. The current study examined the appropriateness of using Mid-Upper Arm Circumference for the identification, follow-up and discharge of malnourished children. We also assessed its discrepancy with the Weight-for-Height based diagnosis, the rate of recovery, and the discharge criteria of the children during nutrition rehabilitation. SUBJECTS/METHODS: The study present findings from 156 children (aged 6-59 months) attending a supplementary feeding programme at Makadara and Jericho Health Centres, Eastern District of Nairobi, Kenya. Records of age, weight, height and mid-upper arm circumference were selected at three stages of nutrition rehabilitation: admission, follow-up and discharge. The values obtained were then used to calculate z-scores as defined by WHO Anthro while estimating different diagnostic indices. RESULTS: Mid-upper arm circumference single cut-off (< 12.5 cm) was found to exhibit high values of sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio at both admission and discharge. Besides, children recorded higher rate of recovery at 86 days, an average increment of 0.98 cm at the rate of 0.14mm/day, and a weight gain of 13.49gm/day, albeit higher in female than their male counterparts. Nevertheless, children admitted on basis of low MUAC had a significantly higher MUAC gain than WH at 0.19mm/day and 0.13mm/day respectively. CONCLUSIONS: Mid-upper arm circumference can be an appropriate tool for identifying malnourished children for admission to nutrition rehabilitation programs. Our results confirm the appropriateness of this tool for monitoring recovery trends and discharging the children thereafter. In principle the tool has potential to minimize nutrition rehabilitation costs, particularly in community therapeutic centres in developing countries.