• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.8
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• pp.1080-1089
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• 2013

Interior Permanent Magnet Synchronous Machines (IPMSMs) with rare earth magnet are widely used in electric vehicles and hybrid electric vehicles. IPMSMs having high efficiency, high torque, and a wide speed range are employed in propulsion system. And the rotor in an IPMSM is generally made of a rare earth magnet to achieve a large energy product and high torque. This paper discusses issues regarding design and performance of IPMSMs using different factors of BH magnetic characteristic. It is necessary to choose factors of magnetic material according to permanent magnet shape in rotor for high performance. Response Surface Methodology (RSM) is selected to obtain factors of magnetic material according to variety of rotor shapes. The RSM is a collection of mathematical and statistical techniques useful for the analysis of problems in which a response of interest in influenced by several variables and the objective is to optimize response. Therefore, it is necessary to analyze the torque characteristics of an IPMSM having magnet BH hysteresis curve with different rotor shape. Factors of residual flux density (Br) factor and intrinsic coercive force (Hc) are important parameters in RSM for rotor shape. The rotor shapes for IPMSMs having magnet BH characteristic were investigated using the RSM, and three shapes were analyzed in detail using FEA. The results lead to design consequence of IPMSMs in the various rare earth magnet materials.

• Journal of architectural history
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• v.12 no.4 s.36
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• pp.63-79
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• 2003

Considering the established research about the characteristics of traditional expression in a contemporary korean architecture, there are two critical problems. the one is that the extent of a case is limited to a public building and a large exhibition building. the other is that the angle of research focus on the viewpoint of specific a level. To settle these problems and supplement a established research, this study is to investigate and analyze the characteristics of popular traditional expression in small commercial buildings. In A viewpoint on the expansion of a case and a various angle, A small commercial buildings is selected as a case. because it is felt that the populace's taste vis-a-vis traditional expression. To investigate and analyze, A main analytic criterion is follows. 1) A expressional method on traditional architectural form 2) A expressional aspect by architectural element 3) A expressional aspect in architectural material 4) A expressional aspect in architectural structure. In consequence we can find out the following results in the process of analysis. 1) In expressional method on traditional architectural form, the traditional expression is represented as the imitation and transformation of a traditional folk house forms, and the embodiment of traditional image 2) In expressional aspect by architectural element, the traditional expression elements is mainly represented at a straw roof and a mud-plastered wall 3) the traditional expression material is mainly straw, timber, small wood boards and mud 4) In expressional aspect in architectural structure, the traditional expression is represented from the viewpoint of decorative expression.

• Korea Journal of Hospital Management
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• v.9 no.3
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• pp.49-70
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• 2004

This study analyzes the effect of separation of dispensary from medical practice on hospital management performance. The results are as follow. The earning ratios of large size hospitals become deteriorated significantly after the separation of dispensary. The growth ratios of revenues from inpatient were unchanged, but the growth ratios of revenues from outpatient of large and middle size hospitals were decreased significantly. Hospitals can't sell the medicines to the outpatient after the separation of dispensary, but they can do to the outpatient. The labor cost ratios of small and large size hospitals are increased significantly after the separation of dispensary. There are two reasons for increase of labor cost ratios. One is the decrease of material cost ratio. The other is the increase of doctor's salary. The material cost ratios of every size hospital are decreased significantly after the separation of dispensary. Because medicines costs of outpatients are decreased. The labor cost and doctors' salary per patient of middle and large size hospitals are increased significantly after the separation of dispensary. And average treatment fees per day of inpatients of middle and large size hospitals are increased significantly after the separation of dispensary. But those of outpatients are decreased significantly. Average numbers of outpatients per bed of small and large hospitals are decreased significantly after the separation of dispensary. And average numbers of inpatients per bed of large hospitals are decreased significantly. In summary, as a consequence of separation of dispensary from medical practice, management performances of large size hospitals become deteriorated significantly.

• Atmosphere
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• v.22 no.2
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• pp.199-208
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• 2012

This study was conducted in order to analyze weather characteristics during the reign of King Sejo in the Chosun Dynasty based on The Annals of the Chosun Dynasty. For this purpose, first of all, we need to determine whether The Annals of the Chosun Dynasty is a reliable material for research on weather characteristics. Thus, we compared weather phenomena during the reign of King Sejo with those in China and Japan in the same period. From the results, it was found that The Annals of the Chosun Dynasty is a useful material at least to grasp macroscopic trends in weather phenomena. Based on this assumption, we analyzed weather characteristics during the reign of King Sejo using data from The Annals of the Chosun Dynasty. During the days of King Sejo, the climate was not changed violently and there were not many disasters caused by abnormal climate such as bad harvests. This suggests that the climate was relatively stable during the period of King Sejo. As a consequence of stable weather, famine decreased markedly. However, this was not only because of stable climate but also because of the government's active efforts to reduce disasters. As droughts and floods were not frequent, social costs for recovery from disasters also decreased considerably and the saved money could be invested in the construction of social safety nets for the prevention of disasters. One of factors supporting the enthronement of King Sejo was a series of heavily damaging bad harvests during the reign of Kings Munjong and Danjong. The prevention of bad harvests was a historical mission given to the regime of King Sejo. During his reign, King Sejo promoted various policies in order to stop bad harvests. Such efforts included the government's active construction of embankments, introduction of seeds suitable for reclaimed lands, and inspiration of the consciousness of forceful farming enduring natural disasters such as floods. As a result, abnormal weathers such as floods and droughts did not lead directly to bad harvests.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.6
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• pp.490-495
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• 2003

The electromagnetic properties and thermal behavior of Mn-Zn ferrite cores for the blocking filter of Power Line Communication(PLC) application were investigated as a function of additives. The highest density and permeability were 4.98 g/$\textrm{cm}^2$ and 8,221, respectively and were obtained to the specimen with composition of MnO 24 mol%, ZnO 25 mol% and Fe$_2$O$_3$ mol%, added MoO$_3$ of 400 ppm, SiO$_2$ of 100 ppm, and CaO of 200 ppm. The uniform grains were organized, and the microstructures were densified due to reduction of pores in the specimen. The permeability was increased up to 13,904 as the temperature of specimen increased to 110$^{\circ}C$. However, it was decreased precipitously under 100 over 110$^{\circ}C$. The exothermic behavior was observed in the frequency range from 1 kHz to 1 MHz, and the maximum temperature of specimen was 102$^{\circ}C$ at 1 MHz. In the consequence, the Mn-Zn ferrite core developed in this research will maintain the stable electromagnetic properties since the temperature of ferrite core rose to 93$^{\circ}C$ in the range of 100 kHz to 450 kHz bandwidth qualified for PLC. The blocking filters were designed for single phase and three phases using the in-line and non-contact core. The best attenuation ratios of -46.46 dB and -73.9 dB were measured in the range of 100 kHz to 450 kHz bandwidth, respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.4
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• pp.322-328
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• 2000

Welding means that metal parts are joined by melting (with or without a filler material) or that new material is added to a metal part by melting. Welding of metal parts is an important technology method in manufacturing processes of capstan drum for costal vessels. Thermal stresses due to the non-uniform temperature fields during welding influence both the fabrication and the use of the weldment. In the problem of this thermal effect, particularly it is a well known that analysis for temperature gradient, temperature distribution, and the like become consequence factors to a safety and a strength design. This paper analyzes the temperature distribution of welding part in capstan drum for the inshore and costal vessels using finite element method. At early stage of the cooling after welding processes, the abrupt temperature gradient has been shown in vicinity of the bottom face of welding part. Therefore it calculates the numerical value that can be applied to the optimal design of welding parts in the shapes for capstan drum.

• International Journal of Highway Engineering
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• v.19 no.2
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• pp.97-102
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• 2017

PURPOSES : Emulsified asphalt is critical for road construction. The objective of applying asphalt emulsion as an adhesive is to prevent the phenomenon of debonding between the upper and lower layers. The quantity and veriety of bituminous material can be varied according to the type of pavement and site conditions. The objective of this study is to reveal the optimum application rates of the emulsified asphalt materials by types of tack-coats using Interface Shear Strength(ISS). METHODS : In the research, emulsified asphalt was paved on the surface of the divided mixture. The specimens of paving asphalt emulsion were utilized to evaluate the bond strength of tack-coat materials. In the evaluation process, NCHRP Report 712 was utilized to investigate the Interface Shear Strength, which reflects the bond capacity of asphalt emulsion. Then, the optimum residual application rates by tack-coat types were determined using regression analysis. RESULTS :As a consequence of squared R values investigated from 0.7 to 1 as part of the regression analysis, the tendency of predicted ISS values was compared with the results. The optimum residual application rates of AP-3, RS(C)-4, QRS-4, and BD-Coat were determined to be $0.78{\ell}/m^2$, $0.51{\ell}/m^2$, $0.53{\ell}/m^2$, and $0.73{\ell}/m^2$, respectively, utilizing 4th regression analysis. CONCLUSIONS :Based on the result of this study, it was not feasible to conclude whether higher residual application of tack-coat material leads to improved bond capacity. Rather, the shearing strength varies depending on the type of pavement.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.3
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• pp.305-312
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• 2010

The aim of this study is to find an analytic solution to the problem of determining the optimal capacity of a batch-storage network to meet demand for finished products in a system undergoing joint random variations of operating time and batch material loss. The superstructure of the plant considered here consists of a network of serially and/or parallel interlinked batch processes and storage units. The production processes transform a set of feedstock materials into another set of products with constant conversion factors. The final product demand flow is susceptible to joint random variations in the cycle time and batch size. The production processes have also joint random variations in cycle time and product quantity. The spoiled materials are treated through regeneration or waste disposal processes. The objective function of the optimization is minimizing the total cost, which is composed of setup and inventory holding costs as well as the capital costs of constructing processes and storage units. A novel production and inventory analysis the PSW (Periodic Square Wave) model, provides a judicious graphical method to find the upper and lower bounds of random flows. The advantage of this model is that it provides a set of simple analytic solutions while also maintaining a realistic description of the random material flows between processes and storage units; as a consequence of these analytic solutions, the computation burden is significantly reduced. The proposed method has the potential to rapidly provide very useful data on which to base investment decisions during the early plant design stage. It should be of particular use when these decisions must be made in a highly uncertain business environment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.12
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• pp.786-790
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• 2016

Hole explosion behaviors were observed during drilling fine holes with laser beam on the LTCC green bar of $320{\mu}m$ thick after lamination of green sheets prepared by tape casting of thick film process. The incidence of these hole explosions was inversely proportional to hole sizes. The incidence of hole explosion was 20 % number of hole with the size of $60{\mu}m$ exploded for the UV radiation, while the explosion did not appear for hole sizes over $100{\mu}m$. To prevent hole explosion behavior during laser-drilling of fine holes, carbon black powder was added as an additive in the LTCC composition, which has superior thermal durability. As a consequence, hole explosion rate was suppressed to 0.8 % for the hole size of $50{\mu}m$ green sheet with the carbon black amount of 10 weight % and the laser power of 3 watt. Added carbon is thought to reduce the heat-affected region during laser drilling.

• Physical Therapy Korea
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• v.14 no.3
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• pp.72-80
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• 2007

The purpose of this study was to verify the effects on fine motor, muscle strength (hand-grip), explosive muscular strength (vertical jump) and muscular endurance (sit-up) after ingesting coffee. Hence this study targeted a sample group of 38 healthy men in their twenties, without cardiac disorders and muscle disorders and none of them were hypersensitive to caffeine with symptoms such as palpitation and dyspnea. Nineteen of them ingested coffee, whereas the other nineteen men ingested decaffeinated coffee at the same amount. The amount of coffee was controlled by weight so as to regulate intake to 6 mg caffeine per kg. Research material was evaluated through O'Conner's finger dexterity test, hand-grip strength test, vertical jump test and sit-up test. The data were analyzed by means of paired t-test and ANCOVA. The material was then, analyzed by means of two-way ANOVA in order to verify the effect of one or two cups of coffee on fine motor and hand-grip strength. All parameters were measured by an independent observer. The results were as follows: There were no significant differences to fine motor, hand-grip strength, vertical jump, sit-up before and after drinking decaffeinated coffee, but there was a difference to those before and after drinking caffeine coffee. There was no significant difference to hand dexterity and hand-grip strength in one or two cups of coffee. Intake of a certain dosage of caffeine effects activation of muscles working in a short period based on the results. As a consequence, intake of certain dosages of caffeine was beneficial to enhance efficiency of activity during exercises, but it is will be difficult to obtain the desired result with only one or two cups of coffee.