• Tuberculosis and Respiratory Diseases
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• v.44 no.6
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• pp.1318-1325
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• 1997

Background : Since the late 1960s, mechanical ventilation has been accomplished primarily using volume controlled ventilation(VCV). While VCV allows a set tidal volume to be guaranteed, VCV could bring about excessive airway pressures that may be lead to barotrauma in the patients with acute lung injury. With the increment of knowledge related to ventilator-induced lung injury, pressure controlled ventilation(PCV) has been frequently applied to these patients. But, PCV has a disadvantage of variable tidal volume delivery as pulmonary impedance changes. Since the concept of combining the positive attributes of VCV and PCV(dual control ventilation, DCV) was described firstly in 1992, a few DCV modes were introduced. Pressure-regulated volume control(PRVC) mode, a kind of DCV, is pressure-limited, time-cycled ventilation that uses tidal volume as a feedback control for continuously adjusting the pressure limit However, no clinical studies were published on the efficacy of PRVC until now. 'This investigation studied the efficacy of PRVC in the patients with unstable respiratory mechanics. Methods : The subjects were 8 mechanically ventilated patients(M : F=6 : 2, $56{\pm}26$ years) who showed unstable respiratory mechanics, which was defined by the coefficients of variation of peak inspiratory pressure for 15 minutes greater than 10% under VCV, or the coefficients of variation of tidal volume greater than 10% under PCV. The study was consisited of 3 modes application with VCV, PCV and PRVC for 15 minutes by random order. To obtain same tidal volume, inspiratory pressure setting was adjusted in PCV. Respiratory parameters were measured by pulmonary monitor(CP-100 pulmonary monitor, Bicore, Irvine, CA, USA). Results : 1) Mean tidal volumes($V_T$) in each mode were not different(VCV, $431{\pm}102ml$ ; PCV, $417{\pm}99ml$ ; PRVC, $414{\pm}97ml$) 2) The coefficient of variation(CV) of $V_T$ were $5.2{\pm}3.9%$ in VCV, $15.2{\pm}7.5%$ in PCV and $19.3{\pm}10.0%$ in PRVC. The CV of $V_T$ in PCV and PRVC were significantly greater than that in VCV(p<0.01). 3) Mean peak inspiratory pressure(PIP) in VCV($31.0{\pm}6.9cm$ $H_2O$) was higher than PIP in PCV($26.0{\pm}6.5cm$ $H_2O$) or PRVC($27.0{\pm}6.4cm$ $H_2O$)(p<0.05). 4) The CV of PIP were $13.9{\pm}3.7%$ in VCV, $4.9{\pm}2.6%$ in PVC and $12.2{\pm}7.0%$ in PRVC. The CV of PIP in VCV and PRVC were greater than that in PCV(p<0.01). Conclusions : Because of wide fluctuations of VT and PIP, PRVC mode did not seem to have advantages compared to VCV or PCV in the patients with unstable respiratory mechanics.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.477-479
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• 1998

인터넷상에서의 다자간 회의는 수천명의 참가하는 대규모의 회의가 될 수 있으므로 다자간 회의 시스템에서는 확장성이 중요하다. 현재의 인터넷상에서의 다자간 회의 시스템은 대부분 RTP/RTCP를 이용하는데. RTCP를 이용한 피드백 정보 전송의 빈도 수와 전송 시간의 동기화 현상이 다자간 회의 시스템의 확장성에 큰 영향을 준다. 즉, 세션 참가자 수가 증가함에 따라 네트워크에 전송되는 RTCP 패킷의 숫자가 기하급수적으로 증가하게 된다. 피드백 정보의 전송 빈도 수 감소와 동기화 현상을 방지하기 위해 도입한 무작위 지연기법은 너무 단순하여 수많은 참가자들이 동시에 피드백 정보를 교환할 때에 피드백 정보 전송시간의 동기화 현상을 피하지 못해 네트워크에 혼잡 상태를 유발할 수 있다. 이러한 혼잡을 예방하기 위한 기존의 RTP/RTCP 확장 기법의 피드백 정보 전송지연은 송신자가 수신자의네트워크 상태에 따라 효율적으로 전송을 제어할 수 없게 한다. 본 논문에서는 RTP/RTCP 확장성을 증가시키는 기존의 기법들의 성능을 평가하고, 확장성 증가와 동시에 성능이 향상된 RTP/RTCP 확장 기법을 제안한다. 본 논문에서는 확장성 증가와 피드백 지연 정도를 줄이기 위해 빠른 제고 기법을 제안한다. 빠른 재고 기법은 두가지 세부 기법으로 나누어지는데, 첫째는 네트워크의 상태의 변화에 따라 RTCP피드백 정보의 전송지연 정도를 조절하는 것이고, 둘째는 무작위 지연을 선택적으로 조정하려 피드백 정보를 오랜 기간 동안에 보내지 못한 참가자에게 우선권을 주는 것이다. 본 논문에서는 시뮬레이션을 통해 제안된 확장성 기법을 이용할 때에 기존 방식에 비해 거의 비슷한 확장성을 보이면서도 초기 RTCP패킷 전송지연이 50%정도 감소함을 보여준다.구현되고 있다.팔일 전송 기법을 각각 제시하고 실험을 통해 이들의 특성을 비교분석하였다.미에서 uronic acid 함량이 두 배 이상으로 나타났다. 흑미의 uronic acid 함량이 가장 많이 용출된 분획은 sodium hydroxide 부분으로서 hemicellulose구조가 polyuronic acid의 형태인 것으로 사료된다. 추출획분의 구성단당은 여러 곡물연구의 보고와 유사하게 glucose, arabinose, xylose 함량이 대체로 높게 나타났다. 점미가 수가용성분에서 goucose대비 용출함량이 고르게 나타나는 경향을 보였고 흑미는 알칼리가용분에서 glucose가 상당량(0.68%) 포함되고 있음을 보여주었고 arabinose(0.68%), xylose(0.05%)도 다른 종류에 비해서 다량 함유한 것으로 나타났다. 흑미는 총식이섬유 함량이 높고 pectic substances, hemicellulose, uronic acid 함량이 높아서 콜레스테롤 저하 등의 효과가 기대되며 고섬유식품으로서 조리 특성 연구가 필요한 것으로 사료된다.리하였다. 얻어진 소견(所見)은 다음과 같았다. 1. 모년령(母年齡), 임신회수(姙娠回數), 임신기간(姙娠其間), 출산시체중등(出産時體重等)의 제요인(諸要因)은 주산기사망(周産基死亡)에 대(對)하여 통계적(統計的)으로 유의(有意)한 영향을 미치고 있어 $25{\sim}29$세(歲)의 연령군에서, 2번째 임신과 2번째의 출산에서 그리고 만삭의 임신 기간에, 출산시체중(出産時體重) $3.50{\sim}3.99kg$사이의 아이에서 그 주산기사망률(周産基死亡率)이 각각 가장 낮았다. 2. 사산(死産)과 초생아사망(初生兒死亡)을 구분(區分)하여 고려해

• Journal of the Korean School Mathematics Society
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• v.20 no.4
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• pp.445-464
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• 2017

This study targeting 10 high school 3rd grade students who have studied space figures in natural sciences track analyzes the process of analogical discovery from the construction of inscribed and circumscribed circles of a triangle to that of inscribed and circumscribed spheres of a tetrahedron through the analytical method using Geogebra. The subjects are divided into two groups of five, the experimental group consisting of those who have experienced analytical method and the comparative group consisting of those who haven't. This research analyzing the process of constructing inscribed and circumscribed spheres of a tetrahedron. Although students of both groups all have an accurate preliminary knowledge of inscribed and circumscribed circles of a triangle, they have difficulty in constructing inscribed and circumscribed spheres of a tetrahedron. However, the students of experimental group who have studied the constructing process of inscribed and circumscribed circles of a triangle in reverse using analytical method and Geogebra can perform analogical discovery finding out the way to construct inscribed and circumscribed spheres of a tetrahedron using analogy by themselves. They can control and explore space figures by visualization. Also, they can immediately examine and provide feedback on the analogizing process of their own. In addition, the process affects the attitude of students toward mathematics positively as well as gives validity to the result of analogy.

• Archives of design research
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• v.18 no.4 s.62
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• pp.119-128
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• 2005

This paper presents an intuitive 3D modeling interlace based on a field study and prototype development. The process and tools of modeling were observed in workshops of professional design model making, day modeling, wood caning and glass crafting. The Spray Modeling interlace was developed from the observational analysis of the field study. It is a 3D modeling interface which combines particle spraying and day modeling in Virtual or Augmented Reality space. Virtual volume particles are sprayed on frames in Augmented Reality space as day modeling. It adopts a real air spay gun as a tangible interface device which provides coherent sound and air-force feedback. The prototype development and a user study showed that the interface supports new patterns of form development and expression. Control interfaces and requirements of auxiliary devices were found to be improved. This study examines the potential of the new interlace for designers working in 3D virtual and augmented reality. The new spraying interface is also expected to be used as an alternative interface in 3D computer workspace, games, education software and media art.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.40-48
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• 2013

This paper presents multi-channel transimpedance amplifier(TIA) arrays in short-range LADAR systems for unmanned vehicles, by using a 0.18um CMOS technology. Two $4{\times}4$ channel TIA arrays including a voltage-mode INV-TIA and a current-mode CG-TIA are introduced. First, the INV-TIA consists of a inverter stage with a feedback resistor and a CML output buffer with virtual ground so as to achieve low noise, low power, easy current control for gain and impedance. Second, the CG-TIA utilizes a bias from on-chip bandgap reference and exploits a source-follower for high-frequency peaking, yielding 1.26 times smaller chip area per channel than INV-TIA. Post-layout simulations demonstrate that the INV-TIA achieves 57.5-dB${\Omega}$ transimpedance gain, 340-MHz bandwidth, 3.7-pA/sqrt(Hz) average noise current spectral density, and 2.84mW power dissipation, whereas the CG-TIA obtains 54.5-dB${\Omega}$ transimpedance gain, 360-MHz bandwidth, 9.17-pA/sqrt(Hz) average noise current spectral density, and 4.24mW power dissipation. Yet, the pulse simulations reveal that the CG-TIA array shows better output pulses in the range of 200-500-Mb/s operations.

• Korean Journal of Community Nutrition
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• v.22 no.3
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• pp.207-217
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• 2017

Objectives: The aim of this study was to examine self-management status, nutritional knowledge, barrier factors in dietary management and needs of nutritional management program for women with Gestational Diabetes Mellitus (GDM). Methods: A total of 100 women with GDM were recruited from secondary and tertiary hospitals in Seoul. The questionnaire composed of general characteristics, status of self-management, dietary habits, nutrition knowledge, barrier factors in dietary management, needs for nutrition information contents and nutritional management programs. Data were collected by a self-administered questionnaire. All data were statistically analyzed using student's t-test and chi-square test using SAS 9.3. Results: About 35% of the subjects reported that they practiced medical nutrition and exercise therapy for GDM control. The main sources of nutrition information were 'internet (50.0%)' and 'expert advice (45.0%)'. More than 70% of the subjects experienced nutrition education. The mean score of nutrition knowledge was 7.5 point out of 10, and only about half of the subjects were reported to be correctly aware of some questions such as 'the cause of ketosis', 'the goal of nutrition management for GDM', 'the importance of sugar restriction on breakfast'. The major obstructive factors in dietary management were 'eating more than planned when dining out', 'finding the appropriate menu when dining out'. The preferred nutrition information contents in developing management program were 'nutritional information of food', 'recommended food by major nutrients', 'the relationship between blood glucose and food', 'tips on menu selection at eating out'. The subjects reported that they need management program such as 'example of menu by calorie prescription', 'recommended weight gain guide', 'meal recording and dietary assessment', 'expert recommendation', 'sharing know-how'. Conclusions: Based on the results of this study, it is necessary to develop a program that provide personalized information by identifying the individual characteristics of the subjects and expert feedback function through various information and nutrition information contents that can be used in real life.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.4
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• pp.577-582
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• 2016

This Study focused on the development of SMPS (Switching Mode Power Supply) to supply the constant votage and current nevertheless LED fluorescent Light generated the electric noise (with Harmonics) and Inrush current at instant time of turn-on and off. Recently, according to the Green policy in government, the LED fluorescent Lighter showed the rapidly increasing tend as indoor and outdoor Lighter. But, because of costs, LED fluorescent Light not considered and neglected the following items; power factor, efficiency, Harmonics and Inrush current. So, we are developed the SMPS about 3 key issues as follows: 1st, power factor and efficiency is 85%. 2nd, the switching noisy by harmonic is minimized. 3rd, the Inrush current at turn on and off time is reduced the minimum 0.3 A after $100{\mu}sec$ on turnon time. The proposed SMPS adjusted by LNK 409 driver (included the high frequency modulation function). Although, the developed SMPS maintained the about 85% of power factor and efficiency. but, the SMPS must be generated low heat by the variation of minute load current at switching timing. To improve the above weak point, the developed SMPS have the feedback monitoring circuit between input side and output side to maintain the power factor and efficiency. Also, we are studied the time-constant of control circuit to output the constant voltage and current nevertheless the load disturbance of LED lighting. The LED fluorescent Light of 46W is checked the above items.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.376-381
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• 2018

The purpose of this study is to investigate price transmissions between wholesale and retail markets regarding Jeju tangerines by employing co-integration analysis and vector error correction model. The results of this study are summarized as follows: First, the long-run equilibrium relationship was found among wholesale and retail markets in time series for level by distribution channel. Second, a short-run causality relationship was observed between wholesale and retail markets. Third, the long-run causality relationship between wholesale market and retail markets was found bidirectional and feedback effect. These results imply that the wholesale price performs a central role in establishing price in the tangerine market, and the wholesale market influences tangerine price. In conclusion, for the development of a competitive tangerine industry, it is necessary to aggressively promote the policy of supply and demand control of tangerine production through organizing producers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.517-524
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• 2020

In line with the recent wave of the 4th Industrial Revolution, the environment for defense R&D is transforming into a center of high-tech military technology. In particular, developed countries are strengthening control of technology exports and technology transfer to protect advanced defense science and technology. For this reason, the budget demand for securing the ability to develop independently high-tech weapons and core technologies suitable for the future battlefield environment is increasing, and increasing efficiency in R&D investment has been highlighted for efficient distribution of limited budgets. This study examined the efficiency of the defense basic R&D project using the non-parametric approach, DEA. The R&D budget, R&D researcher, and R&D period were selected as the input variables, and the number of papers and patents were used as output variables. The efficiency of basic R&D projects was analyzed through CCR, BCC models, and SE. Lastly, based on the efficiency measurements, the cause of the inefficiency of R&D projects was suggested, and ways to improve efficiency were suggested. This study is expected to be used as useful information that can be applied to project performance management through efficiency analysis of basic defense R&D projects and be reflected in the project planning stage through feedback.

• Journal of Astronomy and Space Sciences
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• v.24 no.1
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• pp.79-90
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• 2007

The AmonRa instrument, the primary payload of the international EARTHSHINE mission, is designed for measurement of deep space albedo from L1 halo orbit. We report the optical design, tolerance analysis and the optical performance of the breadborad AmonRa imaging channel instrument optimized for the mission science requirements. In particular, an advanced wavefront feedback process control technique was used for the instrumentation process including part fabrication, system alignment and integration. The measured performances for the complete breadboard system are the RMS 0.091 wave(test wavelength: 632.8 nm) in wavefront error, the ensquared energy of 61.7%($in\;14\;{\mu}m$) and the MTF of 35.3%(Nyquist frequency: $35.7\;mm^{-1}$) at the center field. These resulting optical system performances prove that the breadboard AmonRa instrument, as built, satisfies the science requirements of the EARTHSHINE mission.