• Asian Pacific Journal of Cancer Prevention
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• 제17권2호
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• pp.867-872
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• 2016

Background: Esophageal cancer is one of the most serious malignancies. Due to the aggressive nature of this cancer, the prognosis is poor. A network meta-analysis with simultaneous comparison of multiple treatments can help determine better treatment options that have higher effects on overall survival of patients with lower adverse events. The aim of this review is to simultaneously compare efficacy and adverse events of treatment interventions for esophageal cancer. Materials and Methods: In this review, only randomized control trials (RCT) will be considered for network meta-analysis. All international electronic databases including Medline, Web of Sciences, Scopus, Cochran's library, EMBASE and Cancerlit will be searched to find randomized control trials which compared two or more treatment interventions for esophageal cancer. A network plot will be drawn for visual representation of all available treatment interventions. Bayesian approach will be used to combine the direct and indirect evidence. Treatment effects (e.g. hazard ratio for time to event outcomes, risk ratio for binary outcomes, and rate ratio for count outcomes with 95% credible interval) will be reported. Moreover, cumulative probability of the treatment ranks will be reported using the surface under the cumulative ranking (SUCRA) graphs. Consistency assumption will be assessed by the loop-specific and design-by-treatment interaction approaches. Conclusions: The results of this study may be helpful for the patients, clinicians and health policy makers in selecting treatments that have the best effect on survival and lowest adverse events.

• 소음진동
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• 제9권1호
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• pp.85-96
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• 1999

For ASME Code pumps in nuclear power plants, inservice test is required to assess the operational readiness in accordance with ASME code and related regulations. The objective of this study therefore, is to develop the technical background of the degradation of pump performances and conditions due to low flow rate operation. In addition. the detection techniques of pump operating conditions are to be developed to enhance the safety and economy of nuclear power plants. A test loop consisted of pump, motor. water tank, flow rate measurements and piping system with flow control devices was established for this study. Two typical pumps, 1-stage volute pump and 3-stage turbine pump, were selected and the test was performed upon two major point of views ; i.e., pump discharge pressure pulsations analysis and pump vibration spectrum analysis. From the test results, it is concluded that (1) the pump vibration affected by the natural frequency of operating pump is significant in the low frequency zone (around 1 Hz) : the vibration amplitude. especially. is an important factor during low flow rate operation. and shall be monitored to ensure that it is within the limit of ASME OM code Part 6, (2) the vibration frequency and pump discharge pressure are affected by vane pass frequency and running speed, (3) the wave phenomena due to the compressiblity of water is anticipated during low flow rate operation. and the pump system shall be designed to prevent it and. finally, (4) the technical background of the degradation of pump performances and conditions due to low flow rate operation is provided.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.309-314
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• 2006

In general DGPS system, the correction message is transferred to users by wireless modem. To cover wide area, many DGPS station should be needed. And DGPS users must have a wireless modem that is not necessary in standalone GPS. But SBAS users don't need a wireless modem to receive DGPS corrections because SBAS correction message is transmitted from the GEO satellite by L1 frequency band. SBAS signal is generated in the GUS(Geo Uplink Subsystem) and uplink to the GEO satellite. This uplink transmission process causes two problems that are not existed in GPS. The one is a time delay in the uplink signal. The other is an ionospheric problem on uplink signal, code delay and carrier phase advance. These two problems cause ranging error to user. Another critical ranging error factor is clock synchronization. SBAS reference clock must be synchronized with GPS clock for an accurate ranging service. The time delay can be removed by close loop control. We propose uplink ionospheric error correcting algorithm for C/A code and carrier. As a result, the ranging accuracy increased high. To synchronize SBAS reference clock with GPS clock, I reviewed synchronization algorithm. And I modified it because the algorithm didn't consider doppler that caused by satellites' dynamics. SBAS reference clock synchronized with GPS clock in high accuracy by modified algorithm. We think that this paper will contribute to basic research for constructing satellite based DGPS system.

• 한국시스템다이내믹스연구
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• 제12권4호
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• pp.5-34
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• 2011

The purpose of this paper is to evaluate the policies for reducing private tutoring expenditure in Roh Mu Hyun and Lee Myeong Bak Government using Causal Loop analysis based on the Systems Thinking perspective. The results are as follows. First, high educational achievers receive more private tutoring than lowers and children who have rich parents have better chance to take private tutoring than the others. It reflects the social characteristics which emphasize the academic ability and educational background. Second, two governments implemented educational policies to control the private tutoring expenditure as balancing loops ; strengthening public education, providing after school programs and EBS KSAT teaching and improving the entrance exam of university. Third, they overlooked the unintended feedback loops coming from 1) incongruity between causes and countermeasures of shadow education 2) wrong perception of substitutional relationship between public education and shadow education 3) side effect of the policy increasing the weight of student record 4) problems of diversifying high schools 5) dilemma of easing the burden of testing through admission officer system. The conclusion is that policies of reducing the private education expenses have failed because two governments don't consider unintended Feedback Loops in the process of making education policies. So we have to make policies based on Systems Thinking and reducing private education expenses should not be the purpose of strengthening the public education.

• 전자공학회논문지SC
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• 제44권5호
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• pp.62-70
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• 2007

본 논문에서는 일정 토크영역에서 승압형 PFC 컨버터와 직접토크제어(DTC) 방법을 사용하여 BLDC 모터의 구동 시스템을 DSP(TMS320F2812)로 구현하였다. 기존의 6단계 PWM 전류제어와 달리 미리 정한 샘플시간 마다 간단한 look-up 표로부터 2상 도통 모드에 대한 인버터의 전압 상태 벡터를 설정함으로써 원하는 전류파형을 만들었으며 이로부터 기존의 전류제어기보다 훨씬 빠른 토크 응답특성을 얻을 수 있었다. 또한 BLDC 모터의 비 이상적인 사다리형 역기전력에 의해 발생되는 저주파 토크변동을 저감하기 위하여 위치 loop-up 표를 사용하였다. 아울러 역률을 보정하기 위해 승압형 PFC 컨버터를 구성하였고 이 때 전파 정류된 입력전압과 출력전압, 인덕터의 전류에 의해 평균전류모드 제어 방식으로 80 kHz마다 PWM 듀티(duty)가 조절 되도록 하였다. 이와 같이 복잡한 제어 알고리즘은 초고속 DSP의 출현으로 PFC와 DTC 알고리즘이 동시에 제어가 가능하며, 본 논문에서는 DTC 알고리즘을 구현할 때 DSP의 일반 범용의 출력포트를 사용하여 구현하였고 단지 PFC에서만 1개의 PWM을 사용하여 디지털 제어기를 구현하였다. 실험을 통해 DTC 알고리즘과 PFC 컨버터를 이용한 BLDC 모터 구동 시스템의 타당성과 효용성을 보였고, 실험결과로부터 PFC 컨버터를 사용하지 않았을 때는 역률이 약 0.77이었으나 PFC 컨버터를 사용하였을 때는 부하변동에 관계없이 약 0.9997로 크게 향상됨을 확인하였다.

• 한국임상약학회지
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• 제22권4호
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• pp.330-339
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• 2012

Background : Hypertension is treated with both lifestyle modification and pharmacotherapy. The Seventh Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC-7), published in 2003, provides a streamlined management approach to hypertension for the primary care physician. The JNC-7 is the gold standard also in Korea. According to the JNC-7, special therapeutic considerations are recommended for high-risk individuals with compelling indications. The presence of compelling indications in any given patient should be considered when selecting specific pharmacotherapy to treat hypertension. However, in patients with compelling indications, it is unknown that hepatotoxicity is caused by Calcium Channel Blocker (CCB), one of 1st anti-hypertensive drugs. Now, the CCB is the most used 1st anti-hypertensive drug in Korea Therefore, we evaluated the changes in blood liver function parameters (ALT, AST, Total bilirubin, serum albumin) for the study group. Methods : We randomly collected and retrospectively analyzed Electronic Medical Record data (n=28,788) of patients, and who took calcium channel blockers(non-dihydropyridines; diltiazem, verapamil, dihydropyridines; amlodipine, barnidipine, benidipine, clinidipine, efonidipine, felodipine, isradipine, lacidipine, lercanidipine, nicardipine, nifedipine, nimodipine), with having liver function tests (LFTs) from July 1st 2009 to June 30th 2010 at the Seoul National University Hospital in Korea. Control groups are two antihypertensive agents: RAS blockade (ARB; candesartan, irbesartan, losartan, olmesartan, telmisartan, valsartan, ACE-I; cilazapril, enalapril, fosinopril, imidapril, perindopril, ramipril) and, Diuretics (loop; furosemide, torsemide, thiazide; hydrochlorothiazide[HCTZ], indapamide). Patients not having LFT results at these three standard points of time(baseline, during, medication, and after finishing medication) were excluded. The collected data were analyzed by using the SPSS (Version12.0) and Microsoft Excel (Version2007). Results : 711 patients who were treated CCB (297), RAS blockade (232) or Diuretics (182) monotherapy were selected for the study. In selected patients, liver damage degree(changes of each LFTs value) was higher in diuretics group than other groups, followed by RAS blockade and CCB. In diuretics group's was loop-diuretics group was higher than thiazide-diuretics group. In CCB group, Nondihydropyridine-CCB's damage degree was higher than Dihydropyrine-CCB's that. Conclusions : Despite the limitations due to the retrospective study, among patients with abnormal LFTs, the use of CCBs led to a less liver damage than other 1st anti-hypertensive agents. It can be recommended CCBs as one of the initial treatments of hypertension in patients with liver disease.

• 한국전자통신학회논문지
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• 제14권2호
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• pp.309-316
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• 2019

본 논문은 로컬 클록 왜곡을 보상하는 낮은 지터 성능의 지연 고정 루프를 제시한다. 제안된 DLL은 위상 스플리터, 위상 검출기(PD), 차지 펌프, 바이어스 생성기, 전압 제어 지연 라인(Voltage Controlled Delay Line) 및 레벨 변환기로 구성된다. VCDL(: Voltage Controlled Delay Line)은 CML(: Current Mode Logic)을 사용하는 자체 바이어스 지연 셀을 사용하여 온도에 민감하지 않고 잡음을 공급한다. 위상 스플리터는 VCDL의 차동 입력으로 사용되는 두 개의 기준 클록을 생성한다. 제안된 회로의 PD는 CML에 비해 적은 전력을 소비하는 CMOS 로직을 사용하기 때문에 PD는 위상 스플리터의 유일한 단일 클록을 사용한다. 따라서 VCDL의 출력은 로컬 클록 분배 회로뿐만 아니라 PD에 사용되므로 레벨 변환기에 의해 레일-투-레일 신호로 변환된다. 제안된 회로는 $0.13{\mu}m\;CMOS$ 공정으로 설계되었으며, 주파수가 1GHz인 클록이 외부에서 인가된다. 약 19 사이클 후에 제안된 DLL은 잠금이 되며, 클록의 지터는 1.05ps이다.

• 한국산학기술학회논문지
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• 제12권1호
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• pp.529-536
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• 2011

본 연구는 수돗물과 SWRO 생산수의 수질 특성을 분석하여 SWRO 생산수가 지닌 강한 부식성을 확인하였으며, 이를 근거로 해수담수화 시설의 유지관리 및 부식제어를 목표로 진행되었다. 연구 초기 과정에서는 철 시편(mild steel coupon)에 대한 회분식 실험(Batch test)과 전기화학 실험을 통해 수돗물과 SWRO 생산수의 부식성을 비교하였다. SWRO 생산수의 부식성 제어를 위한 수단으로써 액상소석회(liquid lime, $Ca(OH)_2$)와 이산화탄소(Carbon Dioxide, $CO_2$)를 주입하는 방법과 액상소석회와 인산염계 부식억제제(Phosphate Corrosion Inhibitor, $P_2O_5$)의 조합에 이산화탄소를 주입하는 두 가지 방법을 비교하였다. 실험을 통한 각 수질의 평가는 부식성 평가 지수인 LSI(Langelier Saturation Index)를 통해 비교하였고 그 결과를 통해 액상소석회와 인산염계 부식억제제의 최적 주입량을 선정하여 모의배관 실험(Loop system test)에 적용하였다. 모의배관 운전 평가 후 장착된 금속배관(steel pipe)은 내부의 스케일에 대한 기기분석(SEM, EDX, XRD) 평가를 수행하여 형성물의 주성분과 산화상 및 원소 함류량을 비교 할 수 있었다. 실험 결과, SWRO 생산수에 부식제어기술을 적용하지 않은 대조군과 비교하여 적정량의 단일 액상소석회를 주입한 경우 평균 97.4%의 높은 부식억제 효과를 나타내었고, 액상소석회 와 부식억제제 조합이 주입된 경우 평균 90.9%의 부식억제 효과를 나타냈다. 모의배관 실험 과정 중 금속배관 내부에 형성된 스케일은 대조군의 경우 주로 철 산화물인 반면, 실험군의 경우 탄산칼슘($CaCO_3$) 피막이 형성되어 부식방지에 효과적임을 확인하였다.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.3104-3104
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• 2001

The research described here was undertaken with the aim of monitoring, optimizing and ultimately controlling the production of heterofermentative microbes used as starters in the salami industry. The use of starter cultures in the fermented meats industry is a well-established technique used to shorten and standardize the ripening process, and to improve and control the organoleptic quality of the final product. Starter cultures are obtained by the submerged cultivation of suitable microorganisms in stirred, and sometimes aerated, fermenters where monitoring of key physiological parameters such as the concentration of biomass, substrates and metabolites suffers from the general lack of real-time measurement techniques applicable to aseptic processes. In this respect, the results of the present work are relevant to all submerged fermentation processes. Previous work on the application of on-line NIR spectroscopy to the lactic acid fermentation (Dosi et al. - Monreal NIR1995) had successfully used a system based on a measuring cell included in a circulation loop external to the fermenter. The fluid handling and sterility problems inherent in an external circulation system prompted us to explore the use of an in-line system where the NIR probe is immersed in the culture and is thus exposed to the hydrodynamic conditions of the stirred and aerated fluid. Aeration was expected to be a potential source of problems in view of the possible interference of air bubbles with the measurement device. The experimental set-up was based on an in-situ sterilizable NIR probe connected to the instrument by means of an optical fiber bundle. Preliminary work was carried out to identify and control potential interferences with the measurement, in particular the varying hydrodynamic conditions prevailing at the probe tip. We were successful in defining the operating conditions of the fermenter and the geometrical parameters of the probe (flow path, positioning, etc.) were the NIR readings were reliable and reproducible. The system thus defined was then used to construct and validate calibration curves for tile concentration of biomass, carbon source and major metabolites of two different microorganisms used as salami starters. Real-time measurement of such parameters coupled with the direct interfacing of the NIR instrument with the PC-based measurement and control system of the fermenter enabled the development of automated strategies for the interactive optimization of the starter production process.

• Journal of Animal Science and Technology
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• 제46권6호
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• pp.937-946
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• 2004

Duroc 품종은 돼지 사육에 있어 산육성과 육질 향상을 위해 이용되고 있다. 본 연구는 육종에 많이 이용되는 Duroc 품종의 모계 특이적인 서열의 검색과 계통유전학적 유연관계의 정립을 위하여 미토콘드리아 유전체의 전체 염기서열을 결정하고 집단 내 다형성을 조사하였다. mtDNA 전체 서열의 길이는 16,584-bp 이고, D-loop과 tRNA, rRNA 유전자 영역에서는 삽입/결실이 확인되었다. 4개의 coding gene (COⅡ, COⅢ, ND3, ND4)에서 불완전한 종결코돈을, ND4L과 ND2 유전자는 선택적 개시코돈 양상을 보였다. Duroc 집단에 대한 분석 결과 조절영역에서의 특이적인 11-bp 중복 단위가 일부 개체(15.2%)에서 발견되었고, ND2의 개시코돈과 CYTB 유전자에서도 다형현상을 보였다. 각각의 유전자 영역에서의 다형성은 서로 연관되어 있었고, 그 결과 Duroc 집단은 크게 두 가지 haplotype으로 구분되었다. 계통수에서 Duroc mtDNA 서열은 유럽계열 cluster에 위치하였으나, haplotype 분석과 기존에 연구결과들을 종합해 보면 Duroc 품종은 여러 모계선조 집단에서 기원한 것으로 보이며, 유럽과 아시아 계열 모두가 품종 형성에 이용된 것으로 사료된다된 것으로 사료된다.