• Proceedings of the KSME Conference
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• 2000.04b
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• pp.514-519
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• 2000

Recently a considerable interest is being concentrated on industrial applications of supersonic Coanda wall jets, but the flow physics are not still understood well. It is of practical importance to evaluate the effectiveness of supersonic Coanda wall jet devices fer such industrial purposes. In the present work, experiments and computations were performed to Set a better understanding of the supersonic Coanda jet physics. The experiments were made using a small blow-down wind tunnel. The operating pressure ratio and the Coanda surface configuration were changed to investigate their influences on the wall jet flows. Two-dimensional Navier-Stokes computations were performed using a TVD finite volume scheme to effectively capture the important wave structures of supersonic Coanda jet flows. Both experimental and computational results showed several important hysterical features of the supersonic Coanda wall jets; the attachment and detachment of supersonic Coanda jet were strongly dependent on the change processes of the operating pressure ratio and the detailed flow configuration.

• Transactions of Materials Processing
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• v.15 no.3 s.84
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• pp.247-254
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• 2006

Rather than traditional manufacturing processes, miniature manufacturing processes usually require sophisticated equipments and characteristics of the processes of high cost and of low productivity. Contrarily, miniature stamping process can be realized in a low cost high productivity with relatively inexpensive equipments. In the meso scale, mechanical properties, especially work hardening characteristics, are discovered to be statically scattered and size dependent by intensive experimental and numerical investigations, which make the stamping process hard to apply to the miniature manufacturing. In this study, dual purpose experimental device that can be used for both miniature scale tensile test and miniature scale stamping by simple change of attachment has been developed. For the tensile test, the elongation has been measured with a combined use of a CCD camera and a linear encoder in order to account for the possibility of slippage between specimen and the grip and to ensure the accuracy of the measurement, while load has been measured with a load cell. To satisfy the required material properties for stamping, optimal annealing condition has been found by examining the microstructure of annealed specimen.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.303-304
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• 2006

In this work, we developed an equipment for automatic quality control of fuel pump motor using vibration analysis. The equipment automatically performs a series of tasks such as aligning and conveying the motor, attachment/detachment of an accelerometer, data acquisition, vibration analysis, and classification, etc. Compared to previous manual operations, the developed system is able to provide considerable savings in both time and cost.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.267.1-267.1
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• 2013

In modern science and technology, the organization of building blocks, such as spherical particles and zeolite, is important to form a nanostructure. So, it is essential to develop methods for organizing them into large scale for many precise applications. Up to now, reflux and stirring is widely used method for organization of colloidal particles. However, because this method is hard to organize building block with high coverage and uniform orientation, it is necessary to research another method. In this work, we synthesized spherical silica particles using St$\"{o}$ber method and organized them on the glass which is coated with 3-chloropropyltrimethoxysilane (CP-TMS) and polyethyleneimine (PEI) using Sonication method. Although spherical silica particles are difficult to attach on the glass due to their small attachment site, we improved this problem by coating PEI. We introduced two mode of reaction promotion, sonication (SO) and sonication with stacking between the bare glass (SS), and investigated degree of coverage (DOC) and degree of close packing (DCP).

• Journal of Biosystems Engineering
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• v.7 no.2
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• pp.36-44
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• 1983

Farm population was rapidly decreasing due to shift of the people from farm sector to the non-farm sector caused by the economic growth of the country. Especially, a great shortage of farm labor in busy farming period in June and October is becoming a serious problem in maintaining or promoting land productivity. The peak of labor requirement in summer is caused by rice transplanting and barley harvesting. In order to reduce the restrictions imposed on farm management by the concurrence of labor requirement and the lack of labor, the experimental study for mechanization of barley harvesting has been carried out in the fields. 1. The machines for barley harvesting were knap-sack type reapers, windrow reaper (power tiller attachment), binder and combine. The order of higher efficiency of machine for barley harvesting was combine, binder, windrow reaper (WR), knapsack type reaper 1(KSTR1), and knap sack type reaper 2(KSTR2; mist and duster attachment). 2. The ratio of grain loss for the manual, binder, and combine plot was about four percent of total field yield. 3. The total yield of barley in 35 days and 40 days harvesting after heading were 514 kg and 507kg per 10 ares respectively. The yield of 35 days-plot was higher than other experimental plots. 4. The lowest yield was recorded in 30 days-plot due to the large quantity of immatured grains and having lighter 1000-grain weight. The ratio of immatured grains was 2.66 percent and 1000-grain weight was 29.4 grams. 5. The total harvesting cost of the windrow reaper was 10,178 won per 10 ares. It was the lowest value compared to other machines. The next were combine, binder, KSTR1, KSTR2, and manual in sequence. As a result, the optimum time of barley harvesting for mechanization was 35-40 days after heading. Combine, binder, and windrow reaper were recommended as the suitable machines for barley harvesting in the work efficiency. However, in total harvesting cost, the windrow reaper was the most promising machine for barley harvesting.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.2
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• pp.47-53
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• 2013

In this work, signal transmission properties of SATA connector have been improved using its differential impedance calculation and its design revision to closer impedance matching. Using 3 dimensional electromagnetic field simulator, the differential mode S-parameter was calculated to investigate its signal fidelity. The differential impedance is calculated from the equation of the odd mode impedance with inductance, capacitance, mutual inductance, and mutual capacitance. The differential impedance of SATA connector was calculated to be $107.3{\Omega}$ and did not meet the design specification with $100{\Omega}{\pm}5%$. In order to achieve its impedance range and improve its signal transmission properties, SATA connector's design has been revised with two different directions and analyzed through the calculation of differential impedance, differential reflection loss, and differential insertion loss.

• Korean Journal of Social Welfare
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• v.58 no.3
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• pp.223-244
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• 2006

The purpose of this study was to investigate the developmental pathways that mediate the effects of child abuse on delinquency. Data from the first wave of 'Seoul Panel Study of Children(SPSC)' were analyzed. The subjects consisted of 1,811 4th grade students from elementary schools. Structural equation model was employed for statistical analyses. The results showed that the relationship between child abuse and delinquency was indirectly mediated by self-esteem, peer rejection, and school attachment. The hypothesized structural model had a good model fit. Abused children were more likely to have low self-esteem, which was associated with higher levels of delinquency. In addition, abused children were more likely to be rejected by peers and to have low school attachment, which was also associated with higher levels of delinquency. Implications for social work practice from this study were discussed.

• Explosives and Blasting
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• v.39 no.4
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• pp.1-11
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• 2021

In this study, the vibration data were obtained to analyze the vibration generated during dismantling of slab using the mechanical dismantling method. The obtained vibration data were classified according to the attachment device and then the waveform and dominant frequency analysis were performed. And the correlation was analyzed by the different methods of measuring the distance between the work section and the measurement point. As a result of the waveform analysis for each attachment device, there was little change in the phase of the vibration waveform and only the change in amplitude, which is the magnitude of the vibration velocity. And as a result of frequency analysis, the frequency band was lower when using a crusher method than a braker method and frequency band were close of the natural frequency of the structure to be dismantled. As a result of the correlation analysis, the separation distance was estimated a higher correlation when evaluated as the path through which the vibration propagates along the structure frame than the straight distance between the measurement point and the working section.

• International Journal of Knowledge Content Development & Technology
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• v.13 no.1
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• pp.59-74
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• 2023

Third places are those that offer a space outside of work and home for people to escape the stress associated with the primary spaces of their lives. Through social interactivity these help in acquiring some emotional support provided by a close and intimate attachment. Such social support can turn into social resources for individuals and can lead to forming communities that may become incubators for social capital through regular visits to shared socializing places. This paper focuses on social interaction that takes place through the third place and the communities that are being created as a contributing factor to knowledge management. The study being reported in this paper investigated the role of coffee shops as third places in building communities and social capital in Kuwait. A mixed-method approach was used to conduct the study. These methods included qualitative methods such as extended conversations in the form of semi-structured interviews and quantitative methods of using questionnaires distributed to coffee shop staff and visitors. Results indicated that importance attached to providing facilities by coffee shops reflected that the owners perceived these as third places. The facilities attracted customers to coffee houses where interactions took place that helped to build communities. The pattern of visits by customers showed that mostly they come in groups and have meetings and gatherings that facilitated and encouraged interactions. The communities that are being built in the coffee shops are indicative of these being perceived as third places by owners, customers, and staff. This study shows the potential of coffee shops as a major sector of the food industry promising a valuable contribution in transformation and transition to a knowl- edge-based economy in Kuwait.

• Journal of KIISE:Software and Applications
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• v.35 no.1
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• pp.50-58
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• 2008

Most of Korean sentences are complex sentences which consisted of main clause and embedded clause. These complex sentences have more than one predicate and this causes various syntactic ambiguities in syntactic analysis. These ambiguities are caused by phrase attachment problems which are occurred by the modifying scope of embedded clause. To resolve it, we decide the scope of embedded clause in the sentence and consider this clause as a unit of syntactic category. In this paper, we use sentence patterns information(SPI) and syntactic properties of Korean to decide a scope of embedded clause. First, we split the complex sentence into embedded clause and main clause by the method that embedded clause must have maximal arguments. This work is done by the SPI of the predicate in the embedded clause. And then, the role of this embedded clause is converted into a noun phrases or adverbial phrases in the main clause by the properties of Korean syntax. By this method, the structure of complex sentence is exchanged into a clause. And some phrases attachment problem, which is mainly caused by the modifying scope, is resolved easily. In this paper, we call this method clausal segmentation for embedded clause. By empirical results of parsing 1000 sentences, we found that our method decreases 88.32% of syntactic ambiguities compared to the method that doesn't use SPI and split the sentence with basic clauses.