• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.2
• /
• pp.161-168
• /
• 2013

Nowadays, one of the most interested area of automobile industry is the production of vehicle which has collision safety and ability to produce less amount of $CO_2$. The achievement of such a dual performance is done by choosing the materials like dual phase steel, ferrite bainite steel, etc. These steels have been used in automotive chassis and body parts, and also used to be formed by hole flanging to meet the goal of strength and design requirement. The formability of sheet material was experimented by hole expansion test and the judgement relies on human eye and his experience. This manual judgement involves many errors and large deviation. This paper develops the automatic crack recognition system which finds a crack based on CCD image to complement the problem of the current method depending on human's sense.

• Journal of East-West Nursing Research
• /
• v.13 no.2
• /
• pp.170-178
• /
• 2007

Purpose: This study was to examine the effects of the Danjeon Breathing Exercise Program on physical fitness, levels of serum lipid and physical symptom of people using public health center at Yangju city. Method: One group pretest-posttest design was utilized for this study. This study has been done from July 6 to September 28, 2005 and the subjects of the study were 28 persons. Danjeon breathing exercise was carried out for 60 minutes a day, 3 times a week for 12 weeks. Physical fitness was measured using the Health Management System developed by the Korea Physical Science Institution. Serum lipid level was measured in public health center at Yangju city. Questions of physical symptom (35 items) were chosen from Cornell Medical Index. The collected data were processed by using the SPSS PC program and analyzed by using Wilcoxon Signed Rank Test. Result: 1. The scores of back strength, flexibility and balance of post-test were more increased after Danjeon breathing exercise than those of pre-test. But the score of muscular endurance of post-test was not significantly increased. 2. The degrees of total cholesterol, LDL-cholesterol and triglyceride of post-test were more decreased after Danjeon breathing exercise than those of pre-test. But the degree of HDL-cholesterol of post-test was not significantly increased in statistics. 3. The score of physical symptoms of post-test was not significantly decreased in statistics after Danjeon breathing exercise than that of pre-test. Conclusion: It is concluded that the Danjeon Breathing Exercise Program could increase the physical fitness and decrease levels of serum lipid. So Danjeon breathing exercise could be utilized to promote physical fittness and to decrease level of serun lipids.

• Journal of the Korean Society of Safety
• /
• v.35 no.3
• /
• pp.6-15
• /
• 2020

This study examined the structural behaviors and ultimate loads of assembled system scaffolds by load tests. Considering the number of bay and bracing installation, four specimens were tested. The bays were divided into 1 bay and 2 bays, with and without the bracing member installed. Failure modes and horizontal displacements show that the whole column buckled without showing no point of inflection in the column, regardless of whether or not braces were installed. Thus, the current design method of selecting the vertical spacing between the horizontal members of the system scaffold as the effective buckling length underestimates the effective buckling length. In case of 1 bay specimens, the ultimate loads between specimens with and with bracing members are similar. However, in case of 2 bay specimens, the specimen with bracing members shows the increased ultimate load of 36% compared with that without bracing members. In addition, as the number of bays in the system scaffold increases, the ultimate load of the unit vertical column increases in case of the specimen with bracing installation. However, in the specimen without bracing members, the ultimate load of the unit column reduces with the increment of the number of bays due to the torsional buckling. Therefore, it is essential to install bracing members to increase the whole strength of system scaffolds and the ultimate load of the unit column.

• Journal of Korean Society for Quality Management
• /
• v.46 no.2
• /
• pp.269-282
• /
• 2018

Purpose: The purpose of this study was to improve the FRP Van's durability by analyzing the problematic parameters, redesigning the rear van, and verifying the design drafts using the CAE analysis & Rig test. Methods: The collected data through the government quality inspection and field spot check were thoroughly analyzed through the characteristics diagram and the improvement suggestions were verified by performing CAE analysis, like the dynamic stiffness, Torsional stiffness, open/close condition's strength, Full car durability and Carrying out the actual test. Results: The results of this study are as follows; The output of CAE analysis shows that improvement suggestions have considerable effects on the reinforcement of FRP structure, and the actual torsion and open/close condition durability test prove that rear van may have durable life which is equivalent to vehicle life cycle. Conclusion: The structural weakness of KLTV's FRP rear van was overcome by applying the stiffener in rear van and changing the bonding method of each FRP pieces. That suggestions were proved using CAE analysis and Rig test.

• The Transactions of the Korea Information Processing Society
• /
• v.3 no.1
• /
• pp.200-210
• /
• 1996

Re-engineering has the potential to improve software productivity and quality y across the entire life cycle. It involves improving the software maintenance process and improving existing systems by applying new technologies and tools to software maintenance. Re-engineering can help us understanding existing systems and discover software components(e.g., design structure, data structure that are common across systems. These common components then can be reused in the development (or redevelopment )of systems, thereby significantly shortening the time and lessening the risk of developing systems. The Object-Oriented paradigm has been known to improve software maintainability. There still exist many problems in recognizing object, attributes and operations that are conceptually integrated and constructing of object class. In this paper, we propose a method that defines a fundamental theories of re-engineering and a concept recognition for object- oriented paradigm. We also describe the re-engineering tool that translates the existing procedure-oriented program into object-oriented system. This tool has a strength to solve the conceptual integrity problem in object-oriented recognition.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.4
• /
• pp.429-435
• /
• 2015

A bellows is an important temperature control component in a Joule-Thomson micro-cryocooler. It is designed using a very thin shell, and the inside of the bellows is filled with nitrogen gas. The bellows is made of a nickel-cobalt alloy that maintains its strength and elastic properties in a wide range of temperatures from cryogenic to $300^{\circ}C$. The pressure of the gas and the volume within the bellows vary according to the temperature of the gas. As a result, the bellows contracts or expands in the axial direction like a spring. To explore this phenomenon, the deformation of the bellows and its internal volume must be calculated iteratively under a modified pressure until the state equation of the gas is satisfied at a given temperature. In this paper, the modified Benedict-Webb-Rubin state equation is adopted to describe the temperature-volume-pressure relations of the gas. Experiments were performed to validate the proposed method. The results of a numerical analysis and the experiments showed good agreement.

• Journal of Korean Physical Therapy Science
• /
• v.26 no.3
• /
• pp.57-69
• /
• 2019

Background: The purpose of this study was to compare and analyze the effects of neck and trunk combined exercise program and single exercise on neck angle and neck and shoulder muscle activity. Design: Randomized controlled trial. Methods: In the single exercise group, the basic stretching, head bending and neck bending exercises were performed. The neck and trunk combined exercise group performed torso strength and trunk stability exercises to stabilize the trunk, and then performed the same neck exercise as the single exercise group. The exercise program was conducted 5 days per week for 2 weeks. One-way repeated ANOVA was used to investigate the statistical analysis of neck angle, neck and upper and middle trapezius muscle activity. Results: 1) There was no significant difference in neck angle degree after exercise in neck single exercise group. 2) In the neck and trunk combined exercise, the neck angle degree decreased continuously with the increase of the experimental period and showed a significant difference. 3) In the single exercise group, the muscles which showed significant difference compared to the post-exercise were the right upper, left and right middle trapezius. 4) In the neck and trunk combined exercise group, the right neck muscles showed significant difference after the exercise before the experiment. Conclusion: It was found that the neck and trunk combined exercise was more effective in reducing neck angle and the muscle activity of the subjects with forward head posture was decreased and increased. However, both exercises showed positive effects.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.10
• /
• pp.2733-2740
• /
• 2009

An advanced and proactive response mechanism against diverse attacks on All-IP network should be proposed for enhance its security and reliability on open network. There are two main research works related to this study. First one is the SPIE system with hash function on Bloom filter and second one is the Sinkhole routing mechanism using BGP protocol for verifying its transmission path. In this study, we proposed an advanced IP Tracing mechanism based on Bloom filter and Sinkhole routing mechanism. Proposed mechanism has a Manager module for controlling the regional router with using packet monitoring and filtering mechanism to trace and find the attack packet's real transmission path. Additionally, proposed mechanism provides advanced packet aggregation and monitoring/control module based on existing Sinkhole routing method. Therefore, we can provide an optimized one in All-IP network by combining the strength on existing two mechanisms. And the Tracing performance also can be enhanced compared with previously suggested mechanism.

• International Journal of Highway Engineering
• /
• v.13 no.4
• /
• pp.41-50
• /
• 2011

It is well-known that pavement is easily damaged by several factors including permanent deformation and fatigue crack, causing service life of the pavement to be shorter than expected. It is very important to predict amount of permanent deformation for designing pavement and developing design method of pavement. A new model of permanent deformation of pavement materials based on concept of shear stress ratio has been proposed because the lower pavement materials are highly affected by shear strength of the material. In this study a large repetitive triaxial load test has been adapted for performing test of permanent deformation of crushed subbase materials. The test procedure which includes concept of shear stress ratio has been newly developed. Several important model parameters can be obtained from the test that can be used for making correct permanent deformation model of the material.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.36D no.7
• /
• pp.80-91
• /
• 1999

We present various optimal grating structures which give the low threshold gain, good modulation characteristics, small effective linewidth enhancement factor, and large fabrication tolerance in complex-coupled MQW DFB lasers with absorptive gratings. To obtain these, we calculate the complex coupling coefficients using the extended additional layer method and the threshold gain including the modal loss in the absorptive grating region for rectangular and trapezoidal gratings. Based on the comparison of the results for various possible absorptive grating structures, the design guidelines are presented to obtain the low threshold gain or large fabrication tolerance. Among the grating structures studied, the double grating structure consisting of the absorptive grating on the index grating has the largest fabrication tolerance for the threshold gain and the coupling strength. The fabrication tolerance for the coupling ratio is very large for all the grating structures studied.