• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 추계학술발표대회 개요집
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• pp.189-191
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• 2005

Dissimilar joining of AI 6013-T4 alloys and austenite stainless steel was carried out using friction stir welding technique. Microstructures near the weld zone and mechanical properties of the joint have been investigated. Microstructures in the stainless steel side and AI alloy were depended on the thermo-mechanical condition which they received. TEM micrographs revealed that the interface region was composed of the mixed layers of elongated stainless steel and ultra-fine grained AI alloy and intermetallic compound layer which was identified as the $Al_{4}Fe$ with hexagonal close packed structure. Mechanical properties were lower than those of 6013 AI alloy base metal, because tool inserting location was deviated to AI alloy from the butt line, which resulted in the lack of the stirring.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2007년 추계학술발표대회 개요집
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• pp.39-41
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• 2007

In this study, actual scale welding were conducted at the USC thermal power plant turbine and main steam pipe casting candidate mock up material 9Cr-1.5Mo-CoVNbNB steel(CB2) and 9Cr-0.5Mo-MVNbN steel(P92). And to evaluate the welding process for the actual production, mechanical property testes were conducted for the weld metal. The Mock-up welding condition successfully led to an excellent structural welding joint between casting and pipe material.

• 한국국방경영분석학회지
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• 제22권1호
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• pp.97-113
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• 1996

Mission effectiveness may be defined as a probability that a system can successfully meet an intended mission demand within a given time when operated under specified conditions. This study deals with the Mission effectiveness of a replenishment ships that is performing several types of missions. The essential attributes and their related factors affecting the replenishment missions are established, and then, a mathematical mission effectiveness model is constructed with a replenishment mission characteristics for a basis. Mission effectiveness for a mission is determined by finding the joint probability measure of the following three attributes : operational readiness of the replenishment ships at the start of a mission ; mission reliability of the replenishment ships ; capability of successfully accomplishing intended objectives given an environmental condition. The model is solved analytically. Operational readiness of the replenishment ships in found by the assumed data. Mission reliability and capability are calculated based on the assumed probability distributions. The model would be a useful tool to evaluate mission effectiveness as it is very a replenishment ships.

• 한국분말재료학회지
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• 제1권2호
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• pp.198-207
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• 1994

In order to find an optimal friction-welding condition for Ni-base ODS alloy (MA 754) produced by mechanical alloying, joint experiments were performed with various conditions of friction pressures (50~500 MPa), friction times (1~5 sec) and upset pressures (50~600 MPa). The optimal friction pressure and upset pressure must be above 400 MPa and 500 MPa, respectively, which are determined by tensile strengths and fracture features of as-welded joints. A maximum stress설h of 975 MPa could be obtained under these pressure conditions at friction time of 2 sec. Microstructural features of bonded interface by optical microscope and SEM revealed that the interface regions of all specimens are consisted with three distinct regions and defects such as voids, cracks and wavy interfaces exist in the joints produced under not-optimized conditions. EDS results showed that these defects include oxides composed with elements of Al, Y and Ti. The hardness on the bonded interface was higher than in the base metal region. Specimens fractured in bonded interface region had lower strength values compared to those fractured in base metal region. Surfaces of the former showed a typical intergranular fracture.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권10호
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• pp.4025-4041
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• 2020

Mobile edge computing (MEC) is capable of providing services to smart devices nearby through radio access networks and thus improving service experience of users. In this paper, an offloading strategy for the joint optimization of computing and communication resources in multi-user and multi-MEC overlapping scene was proposed. In addition, under the condition that wireless transmission resources and MEC computing resources were limited and task completion delay was within the maximum tolerance time, the optimization problem of minimizing energy consumption of all users was created, which was then further divided into two subproblems, i.e. offloading strategy and resource allocation. These two subproblems were then solved by the game theory and Lagrangian function to obtain the optimal task offloading strategy and resource allocation plan, and the Nash equilibrium of user offloading strategy games and convex optimization of resource allocation were proved. The simulation results showed that the proposed algorithm could effectively reduce the energy consumption of users.

• 대한후두음성언어의학회지
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• 제10권2호
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• pp.149-153
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• 1999

Relapsing polychondritis is an uncommon disorder of unknown etiology. That involves multisystem characterized by recurrent inflammation, degenerative change of multiple cartilaginous structures. The most common clinical manifestation is an auricular chondritis. Other involving systems are joint, nose, eye, larynx, trachea, aorta, heart and kidney. A 26-year-old man who complained of hoarseness and sore throat was referred to the ENT department from internal medicine department. On initial video-laryngoscopic and radiologic examination, there was no abnormal finding. Treatment with high doses of corticosteroid and methotrexate was not effective. Symptoms were aggrevated with dyspnea. Three months later, on video-laryngoscopic examination, bilateral cord fixation with swelling was noted. The radiologic finding showed subglottic stenosis due to collapse of anterior wall of cricoid cartilage. The condition was managed with tracheotomy. We report a case of relapsing polychondritis involving larynx and trachea with bilateral vocal cord palsy which was managed with tracheotomy.

• 한국치위생학회지
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• 제14권4호
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• pp.519-526
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• 2014

Objectives : The purpose of the study is to investigate the relationship between employment stress and oral symptoms in health college students. Methods : A self-reported questionnaire was filled out by 275 health college students in Seoul from October 7 to November 29, 2013. The data were analyzed using SPSS WIN 14.0 program. Results : Female students tended to have higher employment stress oral symptoms than male. The higher the employment stress was, the more oral symptoms were. There was a close relationship between personal trait, environmental stress and oral symptoms. Regression analysis showed that tongue, teeth, gum, temporomandibular joint(TMJ) were influenced by the employment stress. Conclusions : It is important to reduce the environmental stress in the students. The students themselves must try to overcome the agonal condition by diverting stress into positive way of living.

• Clinics in Shoulder and Elbow
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• 제19권3호
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• pp.163-167
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• 2016

Septic arthritis in neonates is a rare condition. A failure to make an early diagnosis of septic arthritis in neonates may leave a permanent disability as a result of a delayed treatment. Thus, septic arthritis, requires a prompt diagnosis and a timely treatment especially in this subset of patients. In this case report, we describe our treatment protocol for septic arthritis and concurrent osteomyelitis in the right shoulder of a 28-day-old newborn. Using 2.4 mm wrist arthroscopy, we performed an arthroscopic irrigation and drainage, to remove intra-articular debris and inflammatory tissue, and multiple drilling. We report a satisfactory clinical outcome without any postoperative complications or side effects.

• Clinics in Shoulder and Elbow
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• 제19권2호
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• pp.96-100
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• 2016

We encountered a rare condition of rice body in subacromial and subdeltoid spaces in a patient with unremarkable medical history. Although it is uncommon, there have been continued reports on its formation in certain type of infective and inflammatory arthritis. However, except for a traumatic event, evaluation yielded no known and conceivable cause for his chronic inflammatory bursitis. Relatively typical findings for rice body on magnetic resonance imaging have been described, and in our case the imaging prompted us to schedule early removal, which is generally accepted as the management of choice to prevent further progression of symptoms. The symptoms of the shoulder showed significant improvement, and a close follow-up schedule has been recommended for observation of recurrence and development of any foreseeable underlying cause.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 춘계학술논문 발표대회
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• pp.133-136
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• 2007

It has been applied the self adhesion waterproofing sheet which is developed from exist asphalt waterproofing sheet by heat and torch in domestic construction field. However, the problem of waterproofing have constantly happened due to air pocket condition and defect of joint part in waterproofing construction. Therefore, in this study, we would like to analyze the field application as testing in side of materials and construction method of self adhesion butyl rubber sheet and study of the materials performance.