• Journal of Advanced Marine Engineering and Technology
• /
• 제26권2호
• /
• pp.219-225
• /
• 2002

Parameter tuning methods by Ziegler-Nichols for PID controllers are generally classified into Z-N(1) and Z-N(2). The purpose of this paper is to describe what relations exist between the methods of Z-N(1) and Z-N(2), or how Z-N(1) can be originated from Z-N(2) by analyzing one loop control system composing of P or PI controller and time delay process. In this paper, for the first step to seek mutual relations, the simple formulas of Z-N(2) are transformed into those composing of the same parameters as Z-N(1) which is derived from the analysis of frequency characteristics. Then, the approximation of the actual ultimate frequency is proposed as important premise in the translation between Z-N(1) and (2). Such equalization and approximation brings a simple approximated formula which can explain how Z-N(1) is originated from the Z-N(2) in the form of formula.

• 한국소음진동공학회논문집
• /
• 제23권4호
• /
• pp.356-364
• /
• 2013

This paper presents a tracking gain-up controller design method to control effectively the vibration of tracking actuator caused by external shocks and remaining velocity after seek control. A pole placement constraint is considered to assure a desired transient response against the vibration of tracking actuator. A loop gain-up constraint is introduced to hold the tracking gain-up loop gain and control bandwidth within allowable bounds. The pole placement constraint is expressed by a matrix inequality and the loop gain-up constraint is considered as an objective function so that genetic algorithm can be applied. Finally, a tracking gain-up controller is obtained by integrating a genetic algorithm with LMI design approach. The proposed tracking gain-up controller design method is applied to the track-following system of a DVD recording device and its effectiveness is evaluated through the experimental results.

• Clinical and Experimental Pediatrics
• /
• 제54권2호
• /
• pp.45-50
• /
• 2011

Compared to that in the Caucasian population, type 1 diabetes mellitus (T1DM) incidence rates are very low in Koreans. Therefore, compared to the recent development of pharmacological therapy applicable to Korean children with T1DM, interest in nonpharmacological therapy and psychosocial support systems remains low, as is the development of Korean-style T1DM education programs for therapeutic application. Children who have been newly diagnosed with diabetes are placed in completely new environments for treatment. For appropriate control of diabetes, patients have to self-monitor blood glucose levels and inject insulin several times a day and must use extreme self-control when they eat foods to avoid increases in blood glucose levels. Blood glucose excursions resulting from impaired pancreatic ${\beta}$ cell functions cause mental stress due to vague fears of chronic complications of diabetes. In addition, children with diabetes cannot be excluded from the substantial amount of studies required of Korean adolescents, and the absolute shortage of time for ideal control of diabetes adds to their mental stress. Many of these patients are psychologically isolated in school where they spend most of their time, and they are not appropriately considered or supported with respect to blood glucose control in many cases. In this respect, this author will introduce some of the newest views on nonpharmacological therapy and psychosocial support systems that account for important parts of T1DM management and seek measures to apply them in conformity with the social characteristics of Korea.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
• /
• pp.337-338
• /
• 2006

The purpose of this study is to find out main factors affecting public enterprise's environment, which improves the performance of public enterprise. In detail, under the premises of keeping publicity in Korea Electricity Industry, the main target of this study is to seek after factors enhancing entrepreneurship and deals with publicity which is related with entrepreneurship. Questionnaires are distributed to the employee of public enterprise, public servants, and civil corps. A total of 553 copies are collected. The main contents of questionnaires are related with the effect of publicity and entrepreneurship by government control, competitive environment, and shareholding structure in Korea Electricity Power Corporation(KEPCO). The results of this survey are as follows : First, government control is negatively related to the entrepreneurship while it is positively related to the publicity. Second, this survey shows that competitive environment has a positive influence on promoting both publicity and entrepreneurship. Third, this survey in connection with shareholding structure indicates that present structure in KEPCO has a positive effect on publicity but negative effect on entrepreneurship. According to this empirical results, it is verified that the main issues on the performance of KEPCO are related with the level of government control and competitive environment in its industry.

• 한국의류학회지
• /
• 제34권9호
• /
• pp.1442-1453
• /
• 2010

This study targets adult females and shows the analysis of physical images affecting clothing behavior, satisfaction or dissatisfaction of ready-made clothes, favorite ready-made clothes design, and weight control as well as the result of demographic characteristic influencing clothing behavior. An individual satisfied with their body prefers bright colors and shiny clothes, on the other hand, an individual who is dissatisfied with their body do not like ready-made clothes and favor loose suits. This study shows that individuals not satisfied with their body are afraid of becoming fat and are following a weight control program. The analysis explains that women (who care for their appearance well) pursue aestheticism, superiority, and are more satisfied with ready-made clothes with casual, feminine, and fancy motifs. It also shows that women who have no confidence in their body follow feminine modesty; on the contrary, those who are confident of their body are satisfied with ready-made dresses and prefer a sexy image. As a result, those who do not care about their looks seek feminine modesty, functionality, and easy-management.

• 인터넷정보학회논문지
• /
• 제8권1호
• /
• pp.99-113
• /
• 2007

빠르게 변화하는 e-비즈니스 환경 내 구성(원)들은 다양한 기술을 통하여 웹 환경 내 협업에 필요 한 효과적인 비즈니스 정보의 공유, 전송, 분배의 필요성이 점점 증가하고 있다. 하지만, 신뢰할 수 있는 비즈니스 환경 측면에서 정보보호에 대한 위험은 항상 존재 하고 있다. 본 논문에서는 "e-morketplace"라는 비즈니스 환경 내 안전하고, 효과적인 접근제어 모델을 제안하였다. 이 제안 된 모델은 분산 환경 내 다양한 비즈니스 객체들간의 안전한 접근제어 정책 수립 및 제어 방안을 기술하였다. 또한 정형화 된 접근제어 모델이 실제 비즈니스 환경 내 용이하게 사용 할 수 있도록 아키텍처와 가이드라인을 소개하였다.

• 조명전기설비학회논문지
• /
• 제29권1호
• /
• pp.31-36
• /
• 2015

In this paper, an LED lighting system that is capable of automatic or maunal dimming control using a ultrasonic sensor and Bluetooth wireless communication technology is presented. The LED lighting system consists of a ultrasonic sensor, microcontroller unit, Bluetooth wireless communication, LED driver, and LED light source. By using the implemented LED lighting system sample, it is shown that the automatic and manual dimming control is realized. By using the ultrasonic sensor, the LED lighting is automatically brighter or dimmer depending on the distance between the sensor and an object. When using a smartphone that includes Bluetooth wireless communication function, one can not only manually control the brightness of the LED lighting from level 1 to 10, but also monitor the distance between the sensor and object on the smartphone.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.761-766
• /
• 2005

This paper presents a dynamic precedence queue mechanism to resolve unexpected transmission delay of a lower priority transaction in a CAN based system which keeps a fixed priority in data transactions. The mechanism is implemented in the upper sub-layer of the data link layer (DLL), which is fully compatible with the original medium access control layer protocol of CAN. Thus the mechanism can be implemented dynamically while the data transactions are going on without any hardware modification. The CAN protocol was originally developed to be used in the automotive industry and it was recently applied for a broader class of automated factories. Even though CAN is able to satisfy most of real-time requirements found in automated environments, it is not to enforce either a fair subdivision of the network bandwidth among the stations or a satisfactory distribution of the access delays in message transmissions. The proposed solution provides a superset of the CAN logical link layer control, which can coexist with the older CAN applications. Through the real experiments, effectiveness of the proposed mechanism is verified.

• 대한안전경영과학회지
• /
• 제8권3호
• /
• pp.51-66
• /
• 2006

This study was attempted to analyze risk factors and suggest accident prevention in live line works for power transmission lines to be developed and applied in Korea. Safety problem cannot but occur at development of live line works and application to the field. With respect to this, problems likely to occur in the field among works adopting methods of works including live line works for power transmission lines were investigated and analyzed through documentary survey and risk assessment method. The results are summarized as follows. A risk assessment method model was suggested. This method enables scientific and systematic development of safety control. That is, the owner may autonomously induce safety control and build risk assessment database by work process to use them as best training data for workers. Also, in the field, it may induce all workers to participate in safety program and secure safety by making workers seek for safety working method under smooth flow from looking at risk factors to accident prevention activities. It is deemed that this humble study will prevent both accident and injury likely to occur in live line works for power transmission lines.

• 조명전기설비학회논문지
• /
• 제29권2호
• /
• pp.1-7
• /
• 2015

The Light Emitting Diode(LED) lighting control system proposed in this thesis is made up of a sensor module, a microcontroller, Bluetooth wireless communication, LED Driver, and LED downlight. The sensor module, comprised of an infrared sensor, an illumination sensor, and a temperature sensor, was designed to one Printed Circuit board(PCB). The system is able to identify the environment information collected by the sensor, and make it possible to control lighting automatically and manually through sensors. In addition, depending on users' conditions, a color temperature can be controlled. CS-1000, a spectroradiometer, was employed to measure the changing values of a color temperature in 8 steps. According to a test, it was found that it was possible to change a color temperature from 3187K of Warm White LED to 5598K of Cool White LED. The Bluetooth based wireless communication technique makes it possible to control more lighting devices than other wireless communication techniques does.