• Journal of the Korean Society for Precision Engineering
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• v.27 no.3
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• pp.66-72
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• 2010

Recently, the use of means of transportation of the lightweight aluminum to temper the trend is increasing. More efficient use of lightweight aluminum material to Friction stir welding has been widely attempted. Types of welding tools at the right screw to rotate anti-clockwise direction, when the tensile stress exerted on the location of the top plate to the left in the direction of the welding process to the installation was able to obtain high tensile strength. A5052 to the top of the left in the direction of the welding process to install and, when you installed the right under the A6061 was not easily come up to the top of the A5052. Conversely, at the bottom left to install on top of the A6061 and A5052 have been installed at the bottom of the upper area of the A6061 and A5052 intrude easily form the shape of the hill you can see that it was formed.

• The Journal of the Korean bone and joint tumor society
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• v.3 no.1
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• pp.26-31
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• 1997

One of the most common benign tumors of bone is the osteochondroma which is a cartilage-capped bony projection on the surface of a bone. It may occur in any bone that has been performed from cartilage, but the most common locations are the long bone at the metaphyseal region of the most active growth cartilage, that is, the lower end of femur, the upper end of the tibia, and the upper end of the humerus. Other bones often involved are the ilium, scapula, fibula, and phalanges of hands and feet. But, the vertebral column is very rare location for osteochondroma. Only one case of osteochondroma involving the lumbar spine has been previously reported in Korea. We report an unusual case of osteochondroma arising from the left lamina and inferior articular process of the 3rd lumbar spine causing spinal cord compression.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.2
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• pp.351-358
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• 1994

A probabilistic model and analysis methods to determine the means and variances of the velocity and acceleration in stochastically-defined planar pin jointed kinematic chains are presented. The presented model considers the effect of tolerances on link length and radial clearance and uncertainty of pin location as a net effect on the link's effective length. The determination of the mean values and variances of the output variables requires the calculation of sensitivities of secondary variables with respect to the random variables. It is shown that this computation is straightforward and can be accomplished by a conventional kinematic analysis package with minor modification. Thus, the concepts of tolerance and clearance have been captured by the model and analysis. The only input data are the nominal linkage model and statistical information. The "effective link length" model is shown to be applicable to both analytical solution and Monte Carlo simulation. The results from both methods are compared. This paper Ksolves the higher-order kinematic problems for the probabilistic design analysis of stochastically-defined mechanisms.echanisms.

• Journal of Welding and Joining
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• v.26 no.6
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• pp.54-58
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• 2008

Laser welding with AZ61 filler wire was carried out to improve formability though reduction of porosity and formation of under fill bead. Optimum welding condition and mechanical properties of butt joint for $400{\times}500{\times}1.3mm$ magnesium sheets were studied. Optimal welding conditions of laser power, welding speed, and defocusing length are 1000W, 3m/min, and 2mm, respectively. Results of tensile test indicated that both tensile strength and elongation of specimens welded with filler wire were improved at room temperature because of reduction of porosity and under-filled bead formation in addition to the precipitation hardening and microstructure refinement by Al-Mn and Mg-Al-Zn precipitates. At elevated temperature of $200{\sim}350^{\circ}C$, fracture location of tensile specimen was shifted from weld metal to base metal, indicating less softening of weld metal than base metal.

• The Korean Journal of Pain
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• v.28 no.1
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• pp.52-56
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• 2015

Painful periarticular calcification most commonly occurs within the rotator cuff of the shoulder and rarely around the elbow, hip, foot, and neck. As acute inflammatory reaction develops, severe pain, exquisite tenderness, local swelling, and limitation of motion with pain occur. In case of calcific tendinitis of the shoulder, it can be easily diagnosed according to the symptoms and with x-ray. However, in lesions of the hip, as it is a rare location and usually involves pain in the posterolateral aspect of the thigh, which can simulate radicular pain from a lumbar intervertebral disc, it could be difficult to diagnose. Hence, physicians usually focus on lumbar lesions; therefore, misdiagnosis is common and leads to a delayed management. Here, we report the case of a 30-year-old female patient with calcific tendinitis of the rectus femoris that was successfully managed with ultrasound-guided steroid injection. This study offers knowledge about the rectus femoris calcification.

• Journal of Welding and Joining
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• v.29 no.5
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• pp.82-89
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• 2011

The effect of welding condition on tensile properties of KS5J32 Al Alloy was investigated under various welding conditions. The 1.6 mm thick KS5J32 alloy sheets were joined by friction stir welding (FSW) technique with butt joint. The tool rotation speeds were 1000, 1250 and 1500 rpm, and the welding speeds were varied within the range from 100 to 600 mm/min. Voids mainly occurred at the advancing side of the tool probe, when the tool rotation speed was low, due to insufficient materials flow. When the weld pitch exceeded 0.4 mm/rev, voids were observed under all welding conditions and the area of voids increased with increasing weld pitch. For void-free specimens, fracture always occurred at base materials. However voids affected the location of fractures, base metal or welded zone, when the voids existed within the welds.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.11 s.242
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• pp.1472-1479
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• 2005

Multiple surface crack distributed randomly along a weld toe influences strongly on the fatigue crack propagation life of welded joint. It is investigated by using statistical approaches based on series of systematic experiments. From the statistical results, initial crack numbers and its locations follow the normal distribution, and the probability of initial crack depths and lengths can be described well by tile Weibull distribution. These characteristics are used to calculate the fatigue crack propagation life, in which the mechanisms of mutual interaction and coalescence of the multiple cracks are considered as well as the Mk-factors obtained from a parametric study on the crack depths and lengths. The automatic calculation is achieved by the NESUSS, where the parameters such as the number, location and size of the cracks are all treated as random variables. The random variables are dealt through the Monte-Carlo simulation with sampling random numbers of 2,000. The simulation results show that the multiple cracks lead to much shorter crack propagation life compared with those in single crack situation. The sum of the simulation and tile fatigue crack initiation life derived by the notch strain approach agrees well with the experiments.

• Journal of the Korean Regional Science Association
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• v.8 no.2
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• pp.11-26
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• 1992

In spite of her abundant natural resources for tourist industry, Kangreung and Sokcho area became lagged in economic development during the national industrialization. The major purpose of this study is to exactly purpose of this study is to exactly measure the impacts of tourist industry on regional development. Through the regional input-output analysis, we found some critical facts: (1) Input coefficients are relatively high in those industries as fish products, food and drink products, and printing and publishing. (2) Input coefficients are high in fiber and apparel products, and other manufac-turing. (3) Induced production effects are high in chemical and coal products, fish products, food and fish products, printing and publishing, and public administration for Sokcho. (4) As for the induced employment effect, food and lodging, other services, wholesale and retail show high coefficients. (5) As for the location quotients, food and lodging, fish products, transportation and ware housing are identified as basic industries. Through the questionnaire survey, we also found some important facts: (1) Residents tend to evaluate employment effects higher than the income effects from resort-related development. (2) Pollution, forest demolition, general price increase, and traffic congestions are more serious than ever reported. (3) Willingness to participate in resort development is high, but is discouraged by the lack of regional capital. Based on these findings, we suggest some future directions of tourist industry: (1) blocking the leakage of income produced in tourist and tourist industry, (2) connection between fishery and tourist industry, (3) development of tourist route, and (4) administrative reshuffling that helps joint development between private and public sectors.

• Management & Information Systems Review
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• v.25
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• pp.387-405
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• 2008

Vietnam is gaining much attention as an attractive emerging market that can replace BRICs for the corporations who are destined to always look for a new market in order to secure competitive powers in the global market. The reason for Vietnam's becoming an attractive place for production is that much uncertainty has been found in China, which has been the traditional country that absorbed the most amount of capital investment. Also, the favorable conditions of Vietnam market itself and the environmental changes such as the open-door policy of Vietnam government attract the investment of Korean companies, and Korea currently holds the most amount of cumulative investments in Vietnam. However, it is necessary to remember that Vietnam is still a socialist nation, and many required components for corporate activities are not sufficiently provided in Vietnam market. Also, many unstable environmental factors exist such as the lack of infrastructure, the lack of many required institutions, the prevalent corruption, the excessive processing time and cost for adjusting the investment, the lack of advanced work force, and the underdevelopment of part and material industry. Therefore, those companies who are planning to invest in Vietnam should take a long-term perspective in planning the investment strategies, carry out a detailed market investigation and analysis in advance, diversify the investment areas and investment sectors, carefully make a joint venture and management, carefully determine the factory location, establish a local agency, make co-investments with the part suppliers, etc.

• Structural Engineering and Mechanics
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• v.62 no.2
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• pp.225-236
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• 2017

The purpose of this work is to predict ductile fracture of structural steel under extremely low cyclic loading experienced in earthquake. A cumulative damage model is proposed on the basis of an existing damage model originally aiming to predict fracture under monotonic loading. The cumulative damage model assumes that damage does not grow when stress triaxiality is below a threshold and fracture occurs when accumulated damage reach unit. The model was implemented in ABAQUS software. The cumulative damage model parameters for steel base metal, weld metal and heat affected zone were calibrated, respectively, through testing and finite element analyses of notched coupon specimens. The damage evolution law in the notched coupon specimens under different loads was compared. Finally, in order to examine the engineering applicability of the proposed model, the fracture performance of beam-column welded joints reported by previous researches was analyzed based on the cumulative damage model. The analysis results show that the cumulative damage model is able to successfully predict the cracking location, fracture process, the crack initiation life, and the total fatigue life of the joints.