• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.208-213
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• 2008

In order to assess the reliability of the electronics control unit for vehicles, accelerated life test model and procedure are developed. By using this method, failure mechanism and life distribution are analyzed. The main results are as follows : i) the main failure mechanism is degradation failure that is, junction destruction of a semiconductor resin by high temperature. ii) the life distribution of the electronics control unit for vehicles is fitted well to Weibull life distribution and the accelerated life model of that is fitted well to Arrhenius model. iii) at the result of the life distribution, accelerated life test method is developed, and test time for life assessment will be shortened by 5,000 hours by this test method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.5
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• pp.287-291
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• 2010

In this paper, we designed and implemented mobile object automatic system based on senor networks for telematics. For developing this system, we gather the various sensing data through wireless communication method using zigbee sensor networks and analyze them in monitoring equipment. And we enable the driver to recognize the car state information on the whole by interfacing analyzed data to telematics unit. And, we implemented automatic controller that can control temperature and humidity in car automatically by actuating air conditioner based on the data that was monitored throughout temperature sensor, humidity sensor and brightness sensor based on sensor networks.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.3
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• pp.644-654
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• 2001

In this paper, an electronic control unit of the automobile engine for optimal fuel injection an spark timing control has been designed and developed. This system includes hardware and software for a precise control of fuel injection and ignition timing. Especially, the crank angle sensor provides two separate signals: One is the position signal (POS) which indicates 180 degree pulses per revolution, and the other is the reference signal (REF) that represents each cylinder individually. Consequently, the developed engine control system has been able to control fuel injection and ignition timing more quickly and accurately. Through the experiment, it has been found that the fuel injection duration and the position of MBT have been influenced by coolant temperature, air flow rate and engine speed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.8
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• pp.711-716
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• 2000

A fuzzy defrost control algorithm for the multi-type heat pump system was developed. In the fuzzy defrost control algorithm, the air temperature difference at the outdoor unit and the refrigerant pressure difference at the compressor were used as input variables, and the defrost starting time and the defrost time interval were used as output variables. This fuzzy algorithm was applied to the multi-type heat pump system and tested in the five dynamic environmental chambers. Test results show that the newly developed control algorithm is more effective than the conventional control algorithm in the removal of frost formed at the outdoor unit of the heat pump.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.1
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• pp.1-7
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• 2016

In the dentistry field, an ultrasonic surgery unit is widely used in bone cutting and scaling to reduce operation time and minimize hemorrhage. The purpose of this study was to evaluate bone cutting and the effect of a specimen's temperature on the two-type ultrasonic surgery unit using a handpiece moving system(HMS). A HMS, which can cut the bone, was developed to perform the experimental procedure with precision of motion control. Bone specimens were prepared from a combination of epoxy-hardener and cortical bone of bovine leg. Through the bone-cutting experiment, the cutting depth was evaluated by not only scanning electron microscopy, but also Vernier calipers. Also, the temperature distribution was measured by a thermo-graphic camera. This study may be applied methodically in various experimental evaluations on a performance test by a HMS.

• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2099-2104
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• 2015

The paper presents a monitoring system for the cooling of distribution transformers. The suggested system is controlled by a microcontroller scheme. The system is designed to control the oil temperature. It gives a solution to improve the cooling system by adding a number of fans especially for indoor transformers that are placed in badly-ventilated rooms. Also, the paper includes an alarm system with the possibility of tripping the transformer if it is necessary. The monitoring system consists of acquisition temperature sensor, and on-site unit. The hardware and software of the on-site unit are demonstrated with sufficient illustrations. Small prototype is constructed in the laboratory. Some laboratory experiments are carried out for examining the designed circuit by using Proteus Virtual System Modeling as well as for testing the prototype monitoring system. Concerning this research point, a study is carried out to evaluate the economic feasibility. The results are recorded and associated with many recommendations that may be valuable to electrical distribution (utility) companies.

• Journal of the Korean Wood Science and Technology
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• v.12 no.2
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• pp.3-9
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• 1984

This study was carried out to examine the practicality of DAP[$(NH_4)_2HPO_4$] as fire retardant for plywood by static bending test the redried plywoods which had been soaked in 20% $(NH_4)_2HPO_4$ solution. Being hot/cold soaked in the solution for 3/3, 6/3, 9/3 and 12/3 hours and redried by cyclic press-drying method at the platen temp. of 130, 145, 100 and $175^{\circ}C$, the treated plywoods were tested to offer the mechanical data, that is, $S_{pl}$(stress at proportional limit), MOE(modulus of elasticity), MOR(modulus of rupture) and $W_{pl}$(work per unit volume to proportional limit ) in flexure. The results obtained were summarized as follows. 1. $S_{pl}$ of fire retardant treated plywoods ("FRP" would be used hereinafter) decreased as the platen temperature increased, but it was superior to that of non-treated plywoods(Control) at $160^{\circ}C$ or higher. 2. MOE of FRP decreased roughly with the increase of temperature, hut this tendency was not constant. And the value of FRP was higher than that of Control even at $175^{\circ}C$. 3. MOR of FRP showed same temperature-dependent tendency as MOE, but it was influenced more sensitively at the higher temperature. 4. $W_{pl}$ of FRP also decreased gradually with the increase of platen temperature and the value in DAP 9/3 treatment was Jess than 70% of control plywoods. 5. In view of redrying time and mechanical properties, the most reasonable platen temperature for DAP treated FRP was $160^{\circ}C$ in this study.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.8
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• pp.1042-1050
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• 2003

A heating flow discharged from a 4-way ceiling type indoor unit has been investigated to determine the design parameters for the optimal flow control. The flow was measured by a PIV(particle image velocimetry) system and an experimental model of 1/10 scale with a transparent room was devised by satisfying the Archimedes number. This similarity is generally used in cases where the forced convection has similar magnitude of the natural convection. To optimize the heating flow, several vane angles and vane control algorithms of cross and right angle controls were considered. Regarding the vane angle, experimental results show that 30$^{\circ}$is an optimal angle to avoid re-suction flows without significant increase in flow noise. Temperature distribution measured in the environmental chamber ensures the increased thermal comfort when compared to the case, 60$^{\circ}$angle. At the optimal angle, applying open/close control gives rise to more uniform distribution of the heating flow than without control. Especially, the cross-control seems to be satisfactory for thermal comfort.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.1
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• pp.76-87
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• 1996

Energy analysis for the hot water heating control system of apartment house complex is accomplished by computer simulation. Mathematical model of a boiler, pipe network and a unit-house is developed. The effects of heating control methods on the heating performance and energy consumption of the system are investigated. The heating control methods considered in this study are a continuous heating control, and on-off heating control and an intermittent heating control methods. For each control method, the effects of an outdoor temperature, indoor temperature sensing position and the capacities of the boilers and circulating pumps on the heating performance and energy consumption are obtained and "the best" control method is recommended.commended.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.172-176
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• 2004

In this paper, We are inclined to design automated mushroom-cultivation system technology grafting communication technology as CAN(Control Area Network). Mushroom cultivation automated system have a goal to construct stable crop cultivation system ,as we construct embedded-system that can make into one to advance current system. Its sensor part is composed of temperature , humidity and CO2 concentration sensor and of chilling, heating and unit humidity-controlling unit, ventilation fan. In particular, having saved analized temperature, humidity, CO2 concentration data in each sensor, CAN which can control realtime communication is used to analyze the next mushroom-cultivation.