• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.3
• /
• pp.315-323
• /
• 2004

An electrical cascade impactor is a multi-stage impaction device to separate airborne particles into aerodynamic size classes using particle charging and electrical detection techniques. A Faraday cage and an aerosol charger, which are basic components of the electrical cascade impactor, were designed and evaluated in this study. The low-level current response of the Faraday cage was investigated with changing particle size and air flow rate by using sodium chloride (NaCl) particles. The response of the prototype Faraday cage was very similar to that of a commercial aerosol electrometer (TSI model 3068) within ${\pm}$5% for singly-charged particles. The response linearity of the prototype Faraday cage could be extended up to flow rate of 30 L/min. For the performance evaluation of the aerosol charger the monodisperse liquid dioctyl sebacate (DOS) particles, with diameters of 0.1∼0.8$\mu\textrm{m}$, were generated using spraying from an atomizer followed by evaporation-condensation process. Typical performance parameters of the aerosol charger such as P$.$n, wall loss, and elementary charges per particle were evaluated. The performance of the prototype aerosol charger was found to be close to that of the aerosol charger used in an electrical low pressure impactor (ELPI, Dekati).

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.8
• /
• pp.1532-1537
• /
• 2009

Nowadays the diversity and large-capacity of electric appliances are strong effect on electrical fires augment in an alarming way. But, as the inactive response characteristics of the existing RCD (Residual Current protective Device) used on low voltage power distribution lines, so control of overload and electric short circuit faults, major causes of electrical fires, are not enough. Therefore this paper is confirmed the unreliability of the existing RCD by electrical faults simulation and is proposed a auxiliary trip device of RCD by using a high precision current sensor (namely, reed switch) for the prevention of electrical disasters in low voltage power distribution lines caused by overload or electric short circuit faults. The sensitive reed switch in the proposed ATD (auxiliary trip device) exactly detects the increased magnetic flux with the overload or the short current caused by a number of electrical faults, and then rapidly cuts off the existing RCD. The proposed auxiliary trip device of RCD is confirmed the excellent characteristics in response velocity and accuracy in comparison with the conventional circuit breaker through various operation performance analysis. The proposed ATD can also prevent electrical disaster, like as electrical fires, which resulted from the malfunction and inactive response characteristics of the existing RCD.

• Journal of Multimedia Information System
• /
• v.6 no.4
• /
• pp.239-244
• /
• 2019

With the development of Cyber-Physical Systems(CPS), several technologies such as automation control, automotive and intelligent house systems have been developed. To enable communication among various components of such systems, several wired and wireless communication protocols are used. The Controller Area Network(CAN) is one of such wired communication protocols that is popularly used for communication in automobiles and other machinery in the industry. In this paper, we designed and implemented a response time analysis system for CAN communication. The reliable data transfer among various electronic components in a significant time is crucial for the smooth operation of an electric vehicle. Therefore, this system is designed to conveniently analyze the response time of various electronic components of a CAN enabled system. The priority for transmission of the messages in the CAN bus is determined by the message identifier. As the number of nodes increases the transmission of low priority messages is delayed due to the existence of higher priority messages on the bus. We used Raspberry Pi3 and PiCAN2 board to simulate the data transfer for studying the comparative delay in low priority nodes.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.6
• /
• pp.1505-1510
• /
• 2010

Response to nerve stimulation platform for implementing measures to detect finger movement has been functioning as an important factor. The finger movement of the muscle response to nerve stimulation and sensing Actuator for the H/W development is needed. In addition, a low power embedded CPU based on the top was used. H/W configuration portion of the isolation power, constant current control, High impedance INA, amplifier parts, and the stimulus mode and the Micro-control the status of current, AD converter Low Data obtained through the processing system is implemented.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.14 no.2
• /
• pp.134-141
• /
• 2009

The new method is proposed to improve the dynamics of the phase angle detector during abrupt voltage dip caused by a grid fault. Usually, LPF(low pass filter) is used in the feedback loop of SRF(Synchronous Reference Frame) - PLL (Phase Locked Loop) system because the measured grid voltage contains harmonic distortions and sensor noises. A better transient response can be obtained with the proposed design method for SRF-PLL by the analysis of linearized model of the PLL system including LPF. Furthermore, in the proposed method, the controller gain and LPF cut-off frequency are changed from normal value to transient value when the voltage disturbance is detected. This paper shows the feasibility and the usefulness of the proposed methods through the computer simulation and the experiment.

• Asia pacific journal of information systems
• /
• v.16 no.2
• /
• pp.47-67
• /
• 2006

This study takes a quantitative approach to the influence of TTF (Task-Technology Fit) on the individual's use and performance of GSS (Group Support Systems), while traditional studies on TTF have taken the experimental approach to explore the characteristic fit between diverse tasks and technologies. We have the following two research inquires: Are the IS use and performance maximized when information technologies are provided by the exact amount of demand?; and, Does TTF at the high level between task and IT produce better IS use (or performance) than at the low level? To investigate these issues, we use the polynomial regression analysis and response surface methodology of Edwards (1993) instead of traditional direct measure of TTF. This method measures the degree of desired and actual level of information technologies in conducting tasks, and traces the dynamic changes of dependent variables (IS use and performance) according to the variances of each independent variable. Our results conclude that user's IS use and performance are maximized when information technologies are actually provided by no more or less than the desired level. We also found that TTF at the high level promotes better IS use and performance than TTF at the low level.

• The Korean Journal of Food And Nutrition
• /
• v.29 no.1
• /
• pp.104-114
• /
• 2016

In this study, we investigated protection motivation and behavioral intention to prevent serious illnesses related to excessive sodium intake among the university students in Gyeongnam and Busan. Within the protection motivation theory (PMT) framework, a survey questionnaire was developed to measure participants' perceptions on the severity of and the vulnerability to the threat of serious diseases due to the high sodium intake as well as the effectiveness of preventive measures (response efficacy), and the ability to perform them (self-efficacy) along with their willingness to follow recommendations (behavioral intention). Data was collected in June 2015. Study participants were divided into either low (n=117) or high (n=177) sodium intake behavior groups based on their current behaviors. Exploratory factor analysis was performed to measure construct validity and Cronbach's alpha was calculated to check reliability of measurement items. The high sodium intake behavior group perceived higher vulnerability than the low sodium intake behavior group among four PMT factors. Differences of the other three factors were not significant between the two groups. The results of hierarchical regression analysis indicated that self-efficacy and response efficacy affected behavioral intention of high sodium intake behavior among students. Hence, development of strategies to increase self-efficacy and response efficacy are strongly recommended.

• Journal of Chest Surgery
• /
• v.23 no.4
• /
• pp.676-682
• /
• 1990

From August, 1978, to August, 1989, 22 patients underwent pericardiectomy for chronic constrictive pericarditis on the Department of Thoracic and Cardiovascular Surgery, School of Medicine, Keimyung University. There were 14 male and 6 female patients ranging from 11 years to 70 years old[mean age, 44. 1 years]. All patients underwent radical pericardiectomy through a median sternotomy. There was 1 postoperative death[4.s%]. This patient died of low cardiac output 7 days after pericardiectomy. Postoperative complications were hemothorax[2 patients], low cardiac output[2 patients], generalized seizure[1 patient], wound infection[1 patient] and pneumonia[1 patient]. Clinical and pathological findings showed tuberculous origin in 12 patients[54.6%], unknown etiology in 8 patients[36.4%] pyogenic pericarditis in 2 patients[9.1%]. Three hemodynamic responses to pericardiectomy were observed: [1] rapid response, where central venous pressure[CUP] fell below 10 cmH2O by 24 hours in 6 patients; [2] delayed response. Where CVP fell below 10 cmH2O by 48 hours in 12 patients; and [3] no response of CVP in 4 patients. Follow-up ranged from 6 to 62 months with an average of 35.3 months. Postoperative Functional Class was obtained for 21 surviving patients and showed 18 patients[81.8%] to be New York Heart Association functional class I or II.

• The Korean Journal of Food And Nutrition
• /
• v.10 no.2
• /
• pp.151-159
• /
• 1997

In order to compare and examine the general characteristics of myofibrillar proteins which is an important protein source as a food resource and relates directly with muscle contraction, we have extracted the myofibrillar proteins from squid and clam. The ionic strength of myofibrillar proteins connected with Ca-ATPase activity, Mg-ATPase activity and EDTA-ATPase activity showed distinct differences between squid and clam. In the activity-pH curve, actomyosin of the clam had a weak biphasic response. In the low concentration of dioxane, myofibrillar proteins of the squid showed a sudden decrease in activity but myofibrillar proteins of the clam showed in increase in activity. Ethanol and metanol in low concentration caused myosin and HMM from the squid and clam to increase their activities. If we cause modification by NEM, under 10-6M concentration, the activity was increased but above 10-5M concentration, there was a sudden decrease in activity.

• International Journal of Aeronautical and Space Sciences
• /
• v.11 no.1
• /
• pp.49-57
• /
• 2010

Several pyrotechnic devices are employed over the course of satellite's missions, generally for the separation of structural subsystems and deployment of appendages. Firing of pyrotechnic devices results in impulsive loads characterized by high peak acceleration and high frequency content which can cause failures of various flight hardware elements and small components. Thus, accurate prediction of acceleration level in various components of spacecraft due to pyrotechnic devices is important. In this paper, two methods for pyroshock prediction, an empirical model and statistical energy analysis in conjunction with virtual mode synthesis, are applied to predict shock response of a low altitude earth observation satellite during launch vehicle separation. The predicted results are then evaluated through comparison with the shock test results.