• Journal of Korean Society of Steel Construction
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• v.16 no.2 s.69
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• pp.247-255
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• 2004

An experimental program was undertaken to develop seismic retrofit methods of existing steel moment connections with floor slab for improved seismic performance. Five full-scale composite specimens were tested under cyclic loading. Conventional through-diaphragm connections [please check this; no search results were found for through-diaphragm connections] composed of square-tube column and H-beam were retrofitted by adding either a bottom-flange dogbone (RBS) or an improved welded horizontal stiffener at the beam bottom flange. The effectiveness of the proposed retrofit connections schemes was evaluated. The specimen retrofitted using the RBS concept at the bottom flange showed poor connection ductility. In contrast. specimens with the proposed horizontal stiffener details exhibited improved connection ductility.

• Journal of Chest Surgery
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• v.20 no.4
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• pp.695-705
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• 1987

This report provides follow - up data on 37 patients, aged 7 days to 25 years [median: 6.5 months], who underwent repair of total anomalous pulmonary venous connection at Seoul national University Hospital between May, 1978 and June, 1987. The patients were 22 males and 17 females and the sex ratio was 1.6 to 1, showing a male predominance. Sixteen patients had supracardiac, 13 cardiac, 3 infracardiac and 5 had a mixed type. The duration of follow up was from 1 month to 60 months [median: 14 months] There were eight early and one late deaths, and the overall mortality was 24%. The deaths during 1 year of life were eight [89%] and only one death [11%] occurred above 1 year of age. The mortality of cardiac type was unusually high, accounting for 56 percent of the total death, which was probably due to the preoperative poor clinical condition such as pulmonary edema and congestive heart failure. The major cause of death was the perioperative myocardial failure, and the survival was closely related to the preoperative clinical status, age and moderately elevated pulmonary arterial pressure, the sign of the elevated pulmonary vascular resistance and pulmonary venous obstruction. Early diagnosis and early application of surgical intervention is essential to the improved postoperative survival

• Clinical and Experimental Pediatrics
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• v.50 no.9
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• pp.919-924
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• 2007

Pulmonary venous stenosis may be congenital or acquired. Regardless of its origin, the prognosis for patients affected with PVS remains poor. There have been many attempts to palliate PVS with little success. This report describes two patients with PVS which became evident after repair of total anomalous pulmonary venous connection. Intravascular stents were successfully implanted, but progressive restenoses in the stents occurred and eventually both of the patients died. The pertinent literature is reviewed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.5
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• pp.1354-1372
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• 2012

Route establishment in Mobile Ad Hoc Network (MANET) is the key mechanism to a successful connection between a pair of source and destination nodes. An efficient routing protocol constructs routing path with minimal time, less routing overhead and capable of utilizing all possible link connectivity. In general, most on-demand MANET routing protocols operates over symmetrical and bidirectional routing path, which is infeasible due to the inherent heterogeneous properties of wireless devices. Simulation results show that the presence of unidirectional links on a network severely affect the performance of a routing protocol. In this paper, a robust protocol independent scheme is proposed, which enable immediate rediscovery of alternative route for a path blocked by a unidirectional link. The proposed scheme is efficient; route rediscovery is locally computed, which results in significant minimization of multiple route packets flooding. Nodes may exploit route information of immediate neighbors using the local reply broadcast technique, which then redirect the control packets around the unidirectional links, therefore maintaining the end-to-end bidirectional connection. The proposed scheme along with Ad Hoc On-demand Distance Vector (AODV) and AODV-Blacklist routing protocol is investigated over three types of mobility models. Simulation results show that the proposed scheme is extremely reliable under poor network conditions and the route connectivity can be improved by as much as 75%.

• Journal of Agricultural Extension & Community Development
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• v.29 no.1
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• pp.1-18
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• 2022

The government is in the process of pursuing various resident-driven rural development projects for rural development. Accordingly, the government is promoting various software projects to enhance social capital in order to effectively involve residents in rural development projects. However, residents' participation in rural development projects is still passive, while passive residents' involvement creates various problems such as conflicts among residents in the process of project implementation and poor operation after project implementation. This study is intended to be a basis for inducing voluntary community participation in rural development projects by disclosing the intention of residents to participate in the community's internal solidarity with social capital and connection with external communities. According to the analysis of 195 rural residents, three groups were divided according to the level of social capital awareness. While individualist groups with low integration and social capital were 25.1%, they were more integrated, but the average family-oriented group was 42.5%, and social-development groups with high integration and linked social capital were 32.3%. This study is meaningful in that it revealed that the social capital of the resident community is an important factor in both the internal solidarity (integrity) and the external community connection (connectivity) in the rural area development project.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.4 s.50
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• pp.67-76
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• 2006

In this paper the moment transfer efficiency of a web and the strain concentration at the RHS (Rectangular Hollow Section) column-to-steel beam connections was evaluated. Initially, non-linear finite element analysis of five bare steel beam models was conducted. The models were designed to have different detail at their beam-to-column connection, so that the flexural moment capacity was different respectively. Analysis results showed that the moment transfer efficiency of the analytical model with RHS-column was poor when comparing to model with WF(Wide Flnage)-column due to out-of-plane deformation of the RHS-column flange. The presence of scallop and thin plate of RHS column was also a reason of the decrease of moment transfer efficiency, which would result in a potential fracture of the steel beam-to-column connections. Analytical results were compared with the previous experimental results. The analytical and the previous experimental results showed that the strain concentration was inversely proportional to the moment transfer efficiency of a beam web and the deformation capacity of connection was poor as their moment transfer efficiency degrades. Further finite element analyses of composite beam with a floor slab revealed that the neutral axis moved toward the top flange and the moment transfer efficiency of a beam web decreased, which led to premature failure of the connection.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.5
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• pp.563-573
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• 2015

For hard rock subsea tunnels the most challenging rock mass conditions are in most cases represented by major faults/weakness zones. Poor stability weakness zones with large water inflow can be particularly problematic. At the pre-construction investigation stage, geological and engineering geological mapping, refraction seismic investigation and core drilling are the most important methods for identifying potentially adverse rock mass conditions. During excavation, continuous engineering geological mapping and probe drilling ahead of the face are carried out, and for the most recent Norwegian subsea tunnel projects, MWD (Measurement While Drilling) has also been used. During excavation, grouting ahead of the tunnel face is carried out whenever required according to the results from probe drilling. Sealing of water inflow by pre-grouting is particularly important before tunnelling into a section of poor rock mass quality. When excavating through weakness zones, a special methodology is normally applied, including spiling bolts, short blast round lengths and installation of reinforced sprayed concrete arches close to the face. The basic aspects of investigation, support and tunnelling for major weakness zones are discussed in this paper and illustrated by cases representing two very challenging projects which were recently completed (Atlantic Ocean tunnel and T-connection), one which is under construction (Ryfast) and one which is planned to be built in the near future (Rogfast).

• Journal of Oral Medicine and Pain
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• v.43 no.2
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• pp.27-33
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• 2018

Purpose: Many researchers have established a connection between sleep disturbances and the symptoms of temporomandibular disorder (TMD) in adults, but there are a few studies targeted at adolescents with TMD. The aim of this study was to analyze the sleep pattern of adolescents with TMD and to determine the effect of poor sleep quality on their clinical symptoms. Methods: The subjects were composed of 47 adolescents with TMD. The sleep pattern and preliminary information of patients were measured by self-reported questionnaires; Pittsburgh Sleep Quality Index (PSQI) and Questionnaire for TMD analysis. TMD pain was scored using the Numerical Rating Scale. The Kruskal-Wallis test, Mann-Whitney U test, Fisher's exact test and logistic regression were used for statistical analysis. Results: The poor sleeping group had statistically more females (25.00% males, 75.00% females) than the good sleeping group. As compared with that of good sleepers, sleep quality of poor sleepers was significantly worse in the items of subjective sleep quality, sleep latency, sleep duration, sleep disturbances, daytime dysfunction and global PSQI score. The sleep time of adolescents was much longer during vacation ($7.20{\pm}1.38hours$) than during school days ($6.10{\pm}1.26hours$). Poor sleep of patients was associated with the pain in the ear or in front of the ear, in the face, jaw, throat or temple and in neck or back. Adolescents with pain in those areas had significantly higher proportion of poor sleepers than adolescents with no pain in those areas. Conclusions: The high ratio of girls in poor sleeping group could reflect the greater prevalence of TMD in women than in men. Pain in peri-temporomandibular joint areas, neck or back could negatively influence sleep quality of adolescents with TMD.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.5
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• pp.49-59
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• 2015

In this research, the connectivity status between natural environment (forests and rivers) and urban parks in view of ecological networks in a city is evaluated and on the basis of these evaluation results, a future connectivity enhancing recommendations are suggested. As a result, the 96.8% of the connectivity role of the neighborhood parks were core or connected parks and as in terms of the ecological pattern on the outer park, 84.1% of the case neighborhood parks were connected to the ecological element at least one side. Therefore, it can be expected to play a role as corridor that enables the direct connection with the natural environment if the connection plan is well established. As a result of connectivity evaluation of the parks, inside of the parks had low ecological element overall and had low connectivity, outside of the parks had 1.5 times more of low connectivity parks than high connectivity parks, and had similar disconnections such as facilities(fence, soundproof walls, breast walls, etc.), developments(roads, apartment complexes, industrial complexes, etc.), or poor greens regardless of the neighborhood with the ecological elements. To increase the connectivity of ecological network, the cities already built shall secure primarily green territory where can connect with the isolated park due to the surrounding with the developing areas and when planning for new cities or residential complexes, it shall establish a connection plan with the nearby at the beginning.

• Journal of the Korean Society of Safety
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• v.38 no.3
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• pp.27-34
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• 2023

With the technological development of the semiconductor industry, the roles of electrical and thermal energy supply and control of semiconductor equipment in ultrafine processes have become very important. However, instances of electrical fires in the chiller heater, which is used for cooling in the semiconductor manufacturing process, are increasing. A fire occurs in combustibles due to high heat at the connection part of the chiller heater, that is, when the number of electrical wires in the connection part is reduced or when the wires are completely disconnected. In this study, the temperature characteristics were compared and analyzed through experiments and 3D simulations. The number of electrical wires, which is the connection part of the chiller heater, was reduced by 90%, 50%, 30%, 10%, and 5%, and the wires were completely disconnected. When the number of electrical wires was reduced by 5%, heat of up to 80℃ was generated, which is a relatively high temperature but insufficient to cause a fire in combustibles. Complete disconnection occurred due to the vibration of the motor and other components, and sparks and arcs were generated, resulting in a rapid increase in temperature to up to 680℃. When completely disconnected, the temperature increase was sufficient to cause a fire in the combustibles covering the terminal block. Therefore, in this study, the causes of electrical fires in chiller heaters were investigated and preventive measures were proposed by analyzing abnormal signals and thermal characteristics caused by the electrical wiring being reduced and completely disconnected.