• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.12
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• pp.2081-2089
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• 1997

Accurate positioning of the throttle valve of a gasoline engine is required to implement various systems such as traction control system(TCS), cruise control system and drive-by-wire system. In this research, position control system has been developed for the throttle actuator system that uses one throttle actuation for small volume and DC servo motor for fast response. In order to drive the DC motor, PWM signal generator and PWM amplifier were built and interfaced to the motor and controller. Also, time delay control(TDC) law has been used as a basic control algorithm. A method of varying the reference model of the TDC according to the size of change in target throttle angle is proposed here. The simulation and experimental results show that both overshoot prevention and fast response are achieved by the TDC technique with this variable reference model.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.1
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• pp.20-24
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• 2009

sensor node work limited energy. It is undesirable or impossible to replace the batteries that are depleted of energy because of characteristics of the sensor network. Due to the specific energy constrained environment, MAC design for sensor networks generally has to take energy consumption as one of its primary concerns. But in sensor networks, latency has been a key factor affecting the applicability of sensor networks to some delay-sensitive applications. Therefore, we propose MAC protocols based DSMAC in this paper. Which is able to dynamically change the sleeping and duty cycle of sensors is adjusted to adapt to packet amounts in buffer. Proposed MAC has energy efficiency and low latency, compared DSMAC.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.425-426
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• 2016

In this paper, we proposed an algorithm based on movement prediction using Markov chain in delay tolerant networks(DTNs). The existing prediction algorithms require additional information such as a node's schedule and connectivity between nodes. However, network reliability is lowered when additional information is unknown. To solve this problem, we proposed an algorithm for predicting a movement path of the node by using Markov chain. The proposed algorithm maps speed and direction for a node into state, and predict movement path of the node using transition probability matrix generated by Markov chain. As the result, proposed algorithm show that the proposed algorithms has competitive delivery ratio but with less average latency.

• Journal of the Korea Institute of Building Construction
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• v.13 no.4
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• pp.372-381
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• 2013

In the construction industry, a great deal of research has been focused on productivity improvement because a minor change in labor productivity can often make the difference between a profit and a loss. This study shows how productivity measurement methods can be applied in practice, step by step, to analyze and identify potential problems both in productivity and methods performance for masonry work. A work sampling technique was conducted to determine the nature and extent of an observable activity as an aid to measuring overall performance. Also, a method productivity delay model was used to identify non-productivity in individual cycle times. From the work sampling technique, it was found that the masonry crew had a Labor Utilization Factor of 47.1%, and from the videotape analysis, it was found that the material and dumpster location need to be adjusted to reduce the travelling distance. We have found that efforts to improve the productivity of masonry work should be focused almost exclusively on machine and labor delays, based on the result from the method productivity delay model.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.4
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• pp.1025-1029
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• 2007

It is widely assumed that Intelligence Quotient (IQ) is determined by inherent disposition and environmental factor. IQ is estimated by age-conversion score and stabilized around age 4 and IQ of adult age can be predicted after age 10. Though children with Mental Retardation (MR) are delayed in language development since early infant period, they receive only special education including speech and language therapy, but no special medication. In traditional Korean medicine, the etiology and treatment for developmental delay of language have been handed down for a long time. Some studies on herbs and prescriptions for improving language development have been undertaken recently. We have found several cases of significant elevation of IQ in the children treated with long term medications of Korean herbal medicine for improvement of language. Analyzing these cases, especially performance IQ showed significant change. Therefore we suggest that Korean herbal medicine might improve cognition development in children with MR.

• International Journal of Highway Engineering
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• v.15 no.5
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• pp.145-156
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• 2013

PURPOSES : This research is a study on the changes in the road network of the surrounding area is installed according to the Kiss & Ride Zone. METHODS : Estimating the transportation mode of students by using the Metropolitan household Surveys(2006) and estimating the O/D by Kiss & Ride ratio with the estimated data, then being applied to a method of reducing the number of lanes for certain sections of the road which would be installed with Kiss & Ride Zone. RESULTS : The reason why it is different for delay resolving time and the affected roads as the Kiss & Ride percentage change, was the impact of the Kiss & Ride Zone's installation position. CONCLUSIONS : The purpose of the study was to analyze the impact of the road network in accordance with the installation of Kiss & Ride Zone by using speed and queue delay resolving time, and it is a need to develop a quantitative evaluation technique which was using various indicators in impact analysis according to the installation of the traffic safety facilities in the future.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.157-163
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• 2011

Combustion of magnesium dust particle were fabricated test devices and combustion experiments were carried out. The ignition delay time were measured in change of magnesium particle mass flow rate in premixed flame. According to increasing magnesium particle mass flow rate, ignition delay time were more shorter. In addition, magnesium dust combustion temperature were measured different particle sizes and o/f ratio by two wavelength pyrometry. Dust combustion flame temperature is almost similarly, through to equivalence ratio, confirm the combustion flame temperature range characteristics.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.188-198
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• 2016

In soybeans, responses of high temperature according to shift of sowing dates during the growing season was explored using the crop model, CROPGRO-soybean. In addition, it analyzed impact on change of sowing dates affects yield potential of soybean under future climate scenario (2041-2070). In Jeonju and Miryang during 1981-2010, if sowing at 15 or ten days ahead from 10 June, namely in shorten of the sowing day (i.e. when sown on 25 or 30 May), the yield potential reduced. However, the yield potential increased when sown 5 June. In the case of delay of sowing day (i.e. when sown on 15 or 20 June), reduction of yield potential in the average -5% was higher than increase in the average +2%. In particular, the relative changes for shorten of the sowing day or delay of the sowing day do not be shown in normal years which high temperatures did not abnormally occur during the growing season from 2003 to 2010 except when sown on 25 May. In abnormal years which high temperatures occurred during the critical period, especially R5 to R7, shorten of the sowing day affected to the increase of yield potential in Miryang, while the yield potential decreased in Jeonju except when sown on 5 June. However, delay of the sowing day influenced on the reduction of yield potential both in two sites. In future climate scenario of Representative Concentration Pathway (RCP) 8.5 during from 2041 to 2070, the increase and decrease of yield potential for shorten of the sowing day were +10/-9% for RCP 8.5 of Jeonju, and +14/-9% for RCP 8.5 of Miryang, respectively. Additionally, it showed +10/-17% for RCP 8.5 in Jeonju, and +10/-29% for RCP 8.5 in Miryang, respectively in the increase and decrease of yield potential for delay of the sowing day.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.3
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• pp.46-54
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• 1984

A new controller tuning method for solving problems that cannot be applicable to the processes with large time delay by Yuwana-Seborg method is presented. The new method is based on a single experimental test, a step change in the controller set point. Simulation results show that the new method can be not only well applicable to systems including large delay processes but also is superior to Ziegler-Nichols method or Cohen-Coon method in many respects despite unanticipated load disturbances that may occur during the experimental test.

• Management Science and Financial Engineering
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• v.16 no.3
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• pp.1-20
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• 2010

In this paper, the impact of various system parameters such as the parameters of actual demand process, the review periods and the lead times, under each combination of inventory policies and information sharing, on the long run average inventory cost per period incurred at each participant in a supply chain, is considered. For this purpose, numerical studies are conducted, from which some valuable information as to how sensitive our long run average inventory cost per period are as the model parameters change is gleaned, from which, in turn, some managerial insights are gleaned in order for industry practitioners to perform better in supply chain management.