• KDI Journal of Economic Policy
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• v.12 no.1
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• pp.3-29
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• 1990

Korean input-output tables for 1975 and 1985 are first deflated into 1975 constant domestic prices(hypothetical terms), and the constant price I-O data are used to decompose the sources of industrial growth and structural change during the 1975-85 period. Using the same methodology, our results for the 1975-85 period are then linked to the results for the earlier period(1955-75) in order to analyze and evaluate the "demand-side" sources of industrialization over the past three decades. The results from the decomposition of the whole economy indicate that over three decades(1955-85) the relative contribution of domestic demand expansion (DDE) to growth and structural change has continuously declined while the contribution of export expansion(EE) has generally continued to rise. The contribution of import-substitution(IS) which had been significantly higher than that of EE during 1955-63 declined substantially, remaining at an insignificantly low level during the period following 1963. Although it is well known that the government's industrial policy in the 1970s emphasized import-substitution in heavy and chemical industries, no significant changes in the export-oriented growth pattern could be observed even for that period, except for a minor decline in the relative contribution of EE. This may be attributed to the substantially larger, backward-linkage effects of EE than that of IS. The sources-of-growth decompositions for major branches of the manufacturing sector generally support the major conclusions derived from the decomposition for the whole economy. The IS contribution which had been significantly high in almost all manufacturing branches during the 1955-63 period declined to low levels in all but two branches, heavy industry and machinery, during the following period. On the other hand, the relative contribution of EE showed a continuous rise in almost all manufacturing branches(except food processing). Finally, the sources of growth for 1975-85 which were decomposed by detailed sub branches, are analyzed by correlating them with changes in relative prices and industrial protection rates by sub-branches for the same period. A major result is that contrary to general expectations, the EE contributions by sub-branch are not negatively correlated with the nominal rates of protection and/or the effective rates of protection for the same sub-branches. It is also found that no statistically significant, positive correlation exists between IS contributions and nominal protection rates or effective protection rates. These unexpected results may be explained by the peculiar nature of the Korean system of industrial incentives for the past period.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.2
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• pp.241-248
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• 2013

In this study, bearings were developed for a high-power propulsion motor operating in inclined operation conditions through a simulation and similitude-experimental methods using commercial rotating machinery dynamics analysis software. The developed journal bearing is electrically insulated and has low thermal conductivity because each part is connected with 2-4 -mm-thick epoxy plates. To realize an appropriate oil thickness, an oil lift system is adopted, and a half separated structure is applied to ensure the feasibility of maintaining very heavy components. This study discusses some of the key design aspects of sleeve bearing design for high-torque and low-speed propulsion motor applications. Furthermore, the conditions of variable slope tests are examined to prevent oil leakage from the bearing lip seal on the test rig.

• Tribology and Lubricants
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• v.31 no.5
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• pp.213-220
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• 2015

This study evaluates the effect of grooves on the stem part of a plunger on the lubrication characteristics of a fuel injection pump (FIP) by using hydrodynamic lubrication analysis. The current study uses the two-dimensional Reynolds equation to evaluate the changes in lubrication characteristics with variations in clearance, viscosity, and grooves for a laminar, incompressible, and unsteady state flow. This study investigates the lubrication characteristics by comparing the dimensionless minimum film thickness or the film parameter, which is the ratio of the minimum film thickness to surface roughness. The analysis method for the groove section differs depending on the depth of the groove. For instance, in the case of a shallow groove, the film thickness equation considers the depth of the groove, while in the case of a deep grove, it considers the flow continuity. The lubrication characteristics of the FIP are more sensitive to changes in the groove width than to changes in other design variables. Moreover, the application of a groove is more effective under low viscosity conditions. The smaller the distance from the edge of the stem part to the first groove in the case of shallow grooves, the better are the lubrication characteristics of the FIP. In contrast, in the case of deep grooves, the lubrication characteristics of the FIP improve as the distance increases. The application of shallow grooves is more effective for improving the lubrication characteristics than the application of deep grooves.

• Korean Institute of Interior Design Journal
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• v.25 no.5
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• pp.42-54
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• 2016

The purpose of this study is to provide a reference for stage planning by analyzing current state of major theaters' stage space and understanding feedback from directors belonged to theaters. Each room in total 18 theaters' stage facilities was measured and their usage and requirements were analyzed on the spot. In addition, each director provided their experiential knowledge about appropriate stage composition for musical performance. The findings are as follow: under stage machinery is not needed for musical. Tour teams prefer to use their own show-deck for set conversion. On the other hand, over stage flying system needs to be able to deal with dense, fast, and accurate scene change. The size and location of the motor room needs to be carefully considered. The number of set battens is directly linked up with the size of the motor room, which should be located lower than the gridiron. As stage sets get bigger and complicated, the number of works at the gridiron is also increasing. The grating floor has to have enough strength coping with machines lifting heavy sets. Most sound control for musical performance is being done at F.O.H. these days rather that in the sound control room. It should equip enough work area and related infra especially for tour teams. 1st gallery needs to have enough effective width, power infra for lighting fixture, and strong guardrail. Lastly, the whole process of parking-unloading-transporting equipments and sets from loading dock to stage and vice versa needs to be efficient, and this has to be carefully considered from early stage of planning.

• Journal of the Society of Disaster Information
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• v.3 no.1
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• pp.55-68
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• 2007

Recently, people in cities of developed countries are exposed to unfortified damages of crime and disaster due to urbanization, industrialization and information-oriented era caused by congestion of population in terms of hardware and various social pathology phenomena and frequent and large scale of disaster caused by crime and disorder, which occur in the course of going through nuclear family, a gap between rich and poor and aging society in terms of software. In this regard, demand for security upon individual life and property has been increased but the police that are responsible for the public security does not effectively reduce damage in life and property because their activities are mainly oriented in coping with security accidents more than prevention. Shortage of manpower and budget, retarded equipment, and heavy overwork are the reasons. In order to confront with this kind of situation, we should utilize CCTV system with the purpose of declining possible chances of crime, not for eliminating cause of crime as crime prevention activities to predict danger in advance as a way of prevention and we may expect a role of damage prevention by installing CCTV in places where security accident may possibly happen. In conclusion, there are invasion of privacy, misuse of the system, insufficiency of overall monitoring office management, lack of citizens' understanding and economical allotment of the system installation costs in installation of CCTV system. However. it is necessary to install the CCTV system for effective prevention of crime and prevention activities of security accidents and accurate PR of purposes of installing CCTV to local residents, establishing relevant laws about system misuse, allotment of equipment costs and fees by R&D of the system machinery, cost reduction method of storage, management and replacement, saving costs from co-operative attitude of government, and local autonomous entities and local residents should be involved.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.4
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• pp.61-67
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• 2007

Paper sludges collected from three different paper mills were physico-chemically analyzed in order to use them as raw materials for making bed soils and seedling pots. The sludge from a fine paper mill contained lots of inorganic pigment particles used for coating, as those from a newsprint mill and a tissue mill had not. It was clearly through XRD analysis confirmed that all sludges included calcium carbonate. The paper sludge from the tissue mill contained the greatest amount of particles, which would contribute to water absorption and nutrient storage. The sludge from the fine paper mill had the highest density due to many inorganic elements. While the ash content and the total nitrogen content were the highest in the sludge from the fine paper mill, the C/N ratio was the lowest in the fine paper mill sludge. All sludges seemed to have insufficient contents of potassium. The sludges from the newsprint mill and the tissue mill showed more silicon contents than that from the fine paper mill. It was concluded that the sludge from the fine paper mill would be able to be the most efficient raw materials for making bed soils and seedling pots and the other two sludges would be more efficient for intensive culture for crops such as rice and grain with additional supplement of nitrogen and other nutrients.

• Steel and Composite Structures
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• v.23 no.2
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• pp.187-194
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• 2017

To reuse a broken plain concrete (PC) arch, a retrofitting method was proposed to ensure excellent structural performances, in which carbon fiber reinforced polymers (CFRPs) were applied to repair and strengthen the damaged PC arch through bonding and wrapping techniques. Experiments were carried out to reveal the deformation and the load carrying capacity of the retrofitted composite arch. Based on the experiments, repairing and strengthening effects of the CFRP retrofitted broken arch were revealed. Simplified analysing model was suggested to predict the peak load of the CFRP retrofitted broken arch. According to the research, it is confirmed that absolutely broken PC arch can be completely repaired and reinforced, and even behaves more excellent than the intact PC arch when bonded together and strengthened with CFRP sheets. Using CFRP bonding/wrapping technique a novel efficient composite PC arch structure can be constructed, the comparison between rebar reinforced concrete (RC) arch and composite PC arch reveals that CFRP reinforcements can replace the function of steel bars in concrete arch.

• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.616-622
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• 2015

Current ballast water treatment technologies are applying chemical or electrical treatment technology which are not free from secondary environmental pollution. The purpose of this study is to treat the ballast water by shear stress without an additional environmental pollution and to find out the optimal treatment apparatus. We tried to treat ballast water by applying shear stress with two different type of combination of inner and outer cylinder, such as non-pattern type and groove type. In the case of non-pattern type of inner and outer cylinder, sterilization effect was comparatively low because of a slip between inner and outer cylinder. But in the case of groove type of inner and outer cylinder, sterilization effect was superior to the non-pattern type. With a same revolutional speed of 8000rpm, an extinction effect was acquired in the gap of 1 mm of inner and outer cylinder at non-pattern type, but 3mm of that of groove type.

• Journal of Biosystems Engineering
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• v.25 no.6
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• pp.457-462
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• 2000

Boom sprayers have been known by their excellency in field efficiency worker’s safety and pest control efficacy. The boom sprayer in Korea that was developed for paddy field is not suitable for upland field of which shape is irregular and inclination is steep, due to heavy chemical tank long boom width and manual on-off control of spraying. The goal of the study was to develope a boom control system that could control boom angles of left and right boom automatically and independently corresponding to local field slope. The prime mover was selected as a cultivating tractor. Main results of this study were as follows. 1. Ultrasonic sensor whose response time was 0.1s and response angle was within $\pm$20$^{\circ}$was selected to measure distance. Voltage output of the sensor(X, Volt) had a highly significant linear relationship with the vertical distance between the sensor and ground surface(Y, mm) as follows; Y=0.0036X-0.437 2. Left and right section of the boom could be folded up by a position control device(on-off control) which could control the left and right boom independently corresponding to local slope by equalizing distances between the sensor and boom at the center and left/right boom. Most reliable DB(dead band) was experimentally selected to be 75$\Omega$(6cm). 3. At traveling velocity of 0.3~0.5m/s RMS of error between desired and achieved height was less than 4.5cm The developed boom angle controller and boom linkage system were evaluated to be successful in achieving the height control accuracy target of $\pm$10cm.

• Tribology and Lubricants
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• v.30 no.2
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• pp.124-129
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• 2014

The piping system accounts for a large portion of the machinery structure of a plant, and is considered as a very important mechanical structure for plant safety. Accordingly, it is used in most energy plants in the nuclear, gas, and heavy chemical industries. In particular, the piping system for a nuclear plant is generally complicated and uses the reactor and its cooling system. The piping equipment is exposed to diverse loads such as weight, temperature, pressure, and seismic load from pipes and fluids, and is used to transfer steam, oil, and gas. In ultrasound infrared thermography, which is an active thermography technology, a 15-100 kHz ultrasound wave is applied to the subject, and the resulting heat from the defective parts is measured using a thermography camera. Because this technique can inspect a large area simultaneously and detect defects such as cracks and delamination in real time, it is used to detect defects in the new and renewable energy, car, and aerospace industries, and recently, in piping defect detection. In this study, ultrasound infrared thermography is used to detect information for the diagnosis of nuclear equipment and structures. Test specimens are prepared with piping materials for nuclear plants, and the optimally designed ultrasound horn and ultrasound vibration system is used to determine damages on nuclear plant piping and detect defects. Additionally, the detected images are used to improve the reliability of the surface and internal defect detection for nuclear piping materials, and their field applicability and reliability is verified.