• 한국실내디자인학회논문집
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• 제12호
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• pp.50-56
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• 1997

In the past thirty years, apartment house has been greatly developed and the housing supply has improved some degree. However, the fact is that interior space planning of apartment house still has a lot of problems. The purpose of this study is to research the change of interior room. The 160 examples of unit floor plan(40-85m2 i.e. 12.1py-25.7py) were selected and classified according to master bedroom type and living room area when was constructed by the city of Seoul and KNHC from 1970 to 1990. And then, the change of each area, size and ratio were analyzed and researched. The result of this research can be summarized as follows: 1. Size of unit floor plan was on the increase from 16.02py to 17.86py. 2. 2 bedroom type, master bedroom showed a rise of size and occupancy ratio. Living room grew larger than 1982-1991 for size and occupancy ratio. 3. 3 bedroom type, master bedroom was increased in size and occupancy ratio was reduced to 19.99%. Size of living room became broader than master bedroom and occupancy ratio(1972-1981) increased over 1982-1991. Through this analysis and research, this study is to provide the basic data for actural design process and to suggest future trend of apartment house.

• 설비공학논문집
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• 제17권1호
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• pp.56-61
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• 2005

Indoor air quality becomes of a concern recently in view of human health. This study investigates the air diffusion performance and the air change efficiency of a classroom, when outdoor air is introduced in addition to the heating/cooling operation of a ceiling-mounted heat pump. A CFD analysis has been performed to investigate the effect of the discharge angle of the air jets from the heat pump for both parallel and series types of outdoor air system. It is observed that the series type creates more uniform indoor environment compared to the parallel type in general. It can be concluded the discharge angle should not be larger than 40o for the parallel type, in order not to generate thermal stratification in the room.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.318-318
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• 2010

In this paper, we studied generating characteristic of cymbal type piezoelectric transducer according to change of cymbal cap. The transducer is composed of circular piezoelectric ceramic and two elastic bodies which are shaped as cymbal. Two elastic bodies are attached to upper and bottom of the ceramic. Principle of the transducer is to generate expanded displacement because vertical stress is transformed into horizontal stress by slope angle of elastic bodies. The transducer also has advantage of high durability by the angle of elastic bodies. In this study, each parameter was chosen, and then generating characteristics were analyzed by FEM program. The parameters were slope angle of cymbal cap (theta), cap height (h) and cap inner diameter(d). The model that had generating characteristic Of high voltage was chosen by results of the analysis. Besides, maximum vertical displacements according to change of vertical stress were analyzed by structural analysis in order to find out relation between the maximum vertical stress which can prevent from ceramic damage and conditions of each cap.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.320-320
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• 2010

In the case of existing ultrasonic motors, they have characteristics such as outstanding response speed, speed and high efficiency. However, it's very hard to use practically them as small motors due to complicated structure and expensive cost. This paper proposed v-type ultrasonic linear motor. Stator of the motor is composed of thin elastic body and four ceramics attached to upper and bottom areas of the body. The ceramics have each direction of polarization. When two harmonic voltages which had $90^{\circ}$ phase difference were applied to the ceramics, the symmetric and anti-symmetric displacements were generated at the tip to make the elliptical motion. To find out a model that generates maximum displacement at contact tip, FEM program was used with change of leg-angle. In addition, optimal model was chosen by considering magnitude and shape of displacement according to change of frequency.

• 대한가정학회지
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• 제29권3호
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• pp.113-130
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• 1991

The objectives of study were 1) to investigate the motives for moving to the current residence, 2) to analyze residential satisfaction after moving in relation to household characteristics and the motives for moving, and 3) to test relationships among household characteristics, residential satisfaction before moving, motives for moving, and residential satisfaction after moving. Residential satisfaction was evaluated in relation to housing, neighborhood, and socio-psychological environments. Methdo-logy included literature and questionnaire survey. Questionnaires were administered to 269 homemakers living in an apartment complex in seoul. Data were analyzed with the use of SPSSS PC+ computer package. The motives for moving were classified in five types: tenureship improvement, improvement of the physical condition of housing, improvement of neighborhood environment, commuting improvement, and constraints. There were significant differences in the types of motives for moving by socio-economic status, types of houses lived in previously, change in type of tenures, and the duration of residence before moving. There were significant differences in residential satisfaction after moving among types of houses lived in previously, change in type of tenures, and the types of the motives for moving. There were significant relationships among residential satisfaction variables. They were the socio-economic status, change in type of tenures, residential satisfaction before moving.

• Journal of Chest Surgery
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• 제26권7호
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• pp.521-525
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• 1993

Sixty-three patients who underwent open mitral commissurotomy at Sejong General Hospital during last 10 years from the August, 1983 to June, 1993 were reviewed There were fifty-one women and twelve men, and the mean age was 34.2 years. According to the NYHA classification, the distribution of patient preoperatively was as follows: class I, 5 patients ; class II, 26 patients ; class III, 30 patients ; class IV, 2 patients, and mean duration of symptome was 4.5 years. The mean mitral valvular area measured with echocardiogram preoperatively was 0.92cm2. All patients underwent open mitral commissurotomy and 41 patients required additional procedures for relief of subvalvular stenosis or other valvular disease. There were no operative death. 63 patients had three different types of mitral stenosis : type I, mobile cusps without subvalvular change [21 patients] ; typeII, thickened cusps with subvalvular change [34 patients] ; type III, rigid cusps with severe subvalvular change [8 patients]. The valvular calcification was seen in 11 patients [17%] and 15 patients [24%] had left atrial thrombus. The duration of follow-up was from 1 month to 168 months [mean, 39.6 months] and there were no late death. Six patients required reoperation and one patient had embolic episode. Conclusively,the open mitral commissurotomy represents a safe surgical precedure for treating mitral stenosis, allowing a complete removal of atrial thrombosis if present, and even when associated with subvalvular changes.

• 농업과학연구
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• 제40권3호
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• pp.243-252
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• 2013

This study was carried out to investigate safety evaluation of agricultural reservoirs due to raising the embankment. The seepage analysis and large-scale model test were performed to compare and analyze the pore water pressure(PWP), leakage quantity, settlement and piping phenomenon in the inclined core type and the vertical core type embankments. The PWP after raising the embankment showed smaller than before raising the embankment and the stability for piping after raising the embankment. The allowable seepage quantity and the allowable leakage for the steady state and transient conditions is within the range of safe management standard. After raising the embankment in the inclined core, there was no infiltration by leakage. For the vertical core, the PWP showed a large change by faster infiltration of pore water than in the inclined core. In a rapid drawdown, inclined core was remained stable but the vertical core showed a large change in PWP. Settlement after raising the embankment showed larger amounts of settlement than before raising the embankment. The leakage quantity before raising the embankment and the inclined core type showed no leakage. From the result, an instrument system that can accurately estimate a change of PWP shall be established for the rational maintenance and stabilization of raising the embankment for agricultural reservoirs.

• Bulletin of the Korean Chemical Society
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• 제19권7호
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• pp.776-779
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• 1998

Second-order rate constants have been measured spectrophotometrically for the addition reaction of a series of alicyclic amines to 3-butyn-2-one to yield their respective enamines at 25.0 'C. The reactivity of the amines increases with increasing the basicity of the amines. However, the Bronsted-type plot obtained exhibits a downward curvature as the basicity of the amines increases, i.e. βnuc decreases from 0.3 for low basic amines (pKa < 9) and to 0.1 for highly basic amines (pKa > 9). Such a curvature in the Bronsted-type plot is clearly indicative of a change in the reaction mechanism or transition state structure. From the corresponding reactions run in D2O, the magnitude of kinetic isotope effect (KIE) has been calculated to be about 0.8 for highly basic amines and 1.21 for weakly basic amines. The difference in the magnitude of KIE also supports a change in the reaction mechanism or transition state structure upon changing the basicity of the amines. Furthermore, the small KIE clearly suggests that H+ transfer is not involved in the rate-determining step, i.e. the addition reaction is considered to proceed via a stepwise mechanism in which the attack of the amines to the acetylene is the rate-determining step. The curvature in the Bronsted-type plot has been attributed to a change in the degree of bond formation between the amine and the acetylene.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.645-648
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• 2000

A workflow is a flow of work carried out by multiple people. In order to increase efficiency, it is re-quired to change the current workflow dynamically. Till now, three types of dynamic changes: flush, abort, and synthetic cut-over (SCO) , have been proposed. How- ever, the performance evaluations for dynamic workflow changes have not been undertaken. To do so, measuring the amount of time cost making a single change (called change time) and comparing the methods for obtaining such times become ever important. In this paper, we first define change time and then propose a computation method individually for each change type. Finally, we evaluate the performance of an example net change by computing the change times.

• 한국정밀공학회지
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• 제32권8호
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• pp.687-692
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• 2015

LAM (Laser-Assisted Machining) is an effective method for processing difficult-to-cut workpieces. The focal length of a LAM system is changed by the change of the workpiece shape during laser preheating; this problem is solved by changing the lens of the laser module. Linear- and rotary-type lens changers were developed to change the laser lens of a LAM system. The linear-type lens changer is operated by a motor with a ball-screw, and the rotary type is operated by a stepping motor. The natural frequency and structural stability of the laser lens changers were confirmed by using a finite element analysis; in addition, the functions of the lens changers were verified by measuring the iterative accuracy. The measured results show that the rotary-type lens changer is more accurate than the linear-type changer.