• Journal of ILASS-Korea
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• v.19 no.1
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• pp.9-14
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• 2014

Performance of DI diesel engine with high-pressure fuel injection equipment is directly related to its emission characteristics and fuel consumption. So, the electro-hydraulic injector for the common-rail injection system should be designed to meet the precise high fuel delivery control capability. Currently, most high pressure injector in use has a needle driven by the solenoid coil energy or the piezo actuator controlled by charge-discharge of output pulse current. In this study, macroscopic spray approaching method was applied under constant volume chamber to research the performance of three different injectors : solenoid, indirect-acting piezo and direct-acting piezo type for CR direct-injection. LED back illumination for Mie scattering was applied on the liquid spray visible of direct-acting piezo injector, including hydraulic-servo type solenoid and piezo-driven injectors. As main results, we found that a direct-acting piezo injector had better a spray tip penetration than hydraulic-servo injectors in spray visualization.

• Journal of Korean Society of Rural Planning
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• v.21 no.4
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• pp.13-26
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• 2015

This study was conducted to analyze the policy impacts of the '2014 Rural Field Forum'. From 2013, Ministry of Agriculture, Food and Rural Affairs implemented Rural Field Forum to push forward rural development of inhabitants' initiative. In this study, we have evaluated that Rural Field Forum has crucial impacts on residents' competence, region capability and driving force of project by targeting the 374 residents of 350 villages in 9 states who participated in 2014 Rural Field Forum. We also sought for the solution to institutional improvement. Futhermore we analyzed each of leader group and normal residents for departmentalization of policy effects. Taken together, the analysis reveals that: 1)Rural field forum is demonstrated to have a positive effect on the establishment and execution of village development plan and all of its necessary components. 2)Regarding the effect on the village capabilities, the understanding and recognition of village organization was shown to be improved. 3)About regional capabilities, the interest in village project was advanced. 4)In terms of the project execution, Rural field forum turned out to affect the village council processes positively. 5)lastly, between the leader and the residents, the difference effectiveness between them revealed, with the same directivity and considerably bigger effect felt by the leader than by the residents overall.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.1
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• pp.36-41
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• 2008

Cooling tower is an important equipment of the cooling systems for large buildings like factory and department store. Water used for cooling in cooling tower is reused continuously. If the water is polluted, corrosion and scale can happen at equipments and pipes. In order to prevent this problem, it is necessary to control the water quality using chemicals. To control the water quality, an automatic control system is designed, fabricated, and experimented. The control system is based on an imbedded microcontroller. Relays are used for power driving, an LCD and LED for display, and RS485 for remote data acquisition. Monitoring program is also developed for easy man-machine interface and extraction of data stored in the imbedded processor and EEPROM. The control system calculates amounts of chemicals necessary using sensor data and injects the chemicals into the cooling tower on proper time. The developed water quality control system is expected to reduce cost of maintenance and extend the lifetime of the cooling systems with low cost.

• The Journal of the Acoustical Society of Korea
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• v.19 no.4
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• pp.107-114
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• 2000

This work is aimed to develop a new type of the Push-Pull ultrasonic transducer that can provide higher sound pressure level and simpler internal structure than conventional types. The driving part of the newly designed transducer is positioned in the middle of the cylinder, and its optimum geometry is determined by using the FEM package, ANSYS. Through FEM model analysis, the effects of all of its geometrical variables such as transducer length, transducer radius, and the edge shape of the end cap have been examined, and the results have led to the optimum geometry. The newly designed transducer has been found to give better performance than that of traditional ones.

• Asian Journal of Innovation and Policy
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• v.7 no.1
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• pp.103-130
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• 2018

It is generally understood that clusters are the promoters of innovation and therefore, the attention of researchers has been increasingly to discern the factors driving innovation among the firms in a cluster, especially in a high-tech cluster. In this study, we identify the variables capturing the nature of a firm that possibly impact the absorptive capacity of a firm and subsequently ascertain their impact on the degree of interactions between a firm, and other firms and associated institutions within and outside a cluster, respectively. Furthermore, we probe the influence of these interactions as a whole on firm-level innovation. The study was carried out in the context of Bengaluru, which houses the densely interconnected network of innovation-intensive high-tech manufacturing firms forming a high-tech manufacturing cluster. Data were drawn from 101 high-tech manufacturing firms belonging to electronics, machine tools, electrical and pharmaceutical industries. Based on the cluster analysis and subsequent graphical analysis on each of the three profiled clusters, it was found that size and origin of a firm have significant impact on the degree of firm's interactions. In turn, higher dynamism of firms in terms of degree of interactions led to higher innovation performance.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.209-217
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• 2020

North Korea has steadily implemented defense reforms to strengthen its national defense capabilities, and in particular, has made military technology development and military industrial capability strengthening as the focus of national defense reform. North Korea's defense reform ultimately aimed at securing nuclear posture, and as technical achievements accumulated in the Kim Jung-Un era, it led to the development of military strength such as hydrogen bombs and ICBM/SLBM. Having secured nuclear capability, North Korea is also pursuing a symmetricality in the conventional military strength by securing a strategic advantage by pursuing the modernization of the conventional weapon systems through defense reform again. Up to now, North Korea's defense reform has succeeded in establishing a new ruling system for Kim Jung-Un and creating a driving force for negotiations with the United States.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.5
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• pp.1135-1148
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• 2006

The effect of heat on the cancer have been keen since ancient orint medic. Quantitative biologic techniques were applied to the investigation of heat, and the resulting studies have defined a firm rationale for the expectation that hypertherima will be useful in the treatment of cancer. This promise led to activity in developing physical means to produce and measure hyperthermia in patients. Hyperthermic treatments for cancer are grouped into two categories according two the amount of tissue bing heated during the treatments. The categories commonly used are localized, regional, and whole body hyperthermia. Hyperthermia is a situation referring to yang-heat. In orient medic, It refers to vital-qi and the driving force of life activities. Our paper reviewed the present state of the the hyperthemia, outline some major impediments to progress at this time, and suggest researching approches in order to define the role of hyperthermia in the treatment of cancer.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.105-112
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• 2020

The increase in the edentulous jaw which occurs in the aged population has led to personal dental health concerns. In the case of dental implant surgery, the duration of a patient's recovery depends on the surgical plan and their physicical ability. A device may be required to assist a physician in controlling vibration reduction of free-hand drilling and prescribing a good treatment plan that is suitable for the patient's condition. In this work, an artificial tooth-root implant assistant manipulator was studied. The structure and the vibration analysis of the dynamic restraint manipulator that is for drilling the alveolar bone in the mandible bone were performed, and the structural stability was analyzed. Further, a virtual prototype of an artificial tooth-root implant assisted manipulator was fabricated and tested. Hence, the state of the Remote Center of Motion (RCM) point and the driving state of the manipulator were confirmed. Furthermore, the drilling experiments were performed by using materials similar to a human jawbone in order to evaluate the performance of the drilling process that is operated using the assistant manipulator.

• Geomechanics and Engineering
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• v.32 no.1
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• pp.35-47
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• 2023

Deformability of road pavements in the form of ruts represent a safety risk for road users. In the procedures for dimensioning the pavement structure, the requirement that such deformations do not occur is imperatively included, which results in the appropriate selection of elements (material, geometry) of the pavement structure. Deformability and functionality, will depend of the correct design of pavement structure during exploitation period. Nevertheless, there are many examples where deformations are observed on the pavement structure, in the form of rutting at parts of the road with relatively short length, realised in the same climatic and the same geoenvironmental conditions. The performed analysis of deformability led to the conclusion that the level of deformation is a function of the speed of traffic. This effect is observed on city roads, but also outside of urban areas at roads with speed limits are significant, due to the traffic management, traffic jams (intersections, etc.). Still, the lower speed cause greater deformations. The authors tried to describe the deformability of flexible pavement structures, from the aspects of geotechnical problems, as a function of driving speed. Outcome of the analysis is a traffic load correction coefficient, in terms of using the existing methods of flexible pavement structures design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.117-124
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• 2019

Military Vehicles of the Korean army had been developed before 2004 and used manual transmissions. Manual transmissions contain a clutch system regulating the force from engine to transmission. In this study, a 2.5-ton military vehicle's clutch system was investigated. The existing clutch system had the characteristics that need to adjust the clearance between the clutch cover and release bearing. Improper clearance led to early wear of the clutch disk and failure of the clutch cover. To solve these problems, an improved clutch system was suggested and tested. The improved clutch system contains auto adjustment of the clearance and an enhanced clutch disk. To verify the improved clutch systems, 2 stage tests were conducted: an accelerated life test of the clutch system, and a driving test by trainee of driving more than 3,000km. As a result, the problems caused by the improper clearance adjustment were solved and this design was verified.