• Journal of computational fluids engineering
• /
• v.20 no.4
• /
• pp.109-115
• /
• 2015

In this study, the Stokes flow in the microchannel is analysed where the semicircular protuberances with constant spacing are attached on the upper and lower walls with staggered arrangement. For the low Reynolds number flow in microchannel, Stokes approximation is used and the periodicity and symmetry of the flow are considered to determine the stream function and pressure distribution in the flow field by using the method of least squared error. As results, the streamline patterns and pressure distributions in the flow field are shown for some specific values of the size and spacing of the protuberances, and shear stress distributions on the surface of semicircular protuberances are plotted. Especially, for an important physical property, the average pressure gradient along the microchannel is obtained and compared with that for the case of in-phase arrangement of the upper and lower protuberances. And, for the small clearance between the protuberances of upper and lower walls or between the protuberances and the opposite wall, the average pressure gradient is derived from the lubrication theory and compared with that of the present study.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.26 no.4
• /
• pp.113-124
• /
• 1999

The purpose of this study is to search into the relation between the chinese seclusion culture and the gentleman's gardens by means of the historical and aesthetic approach. The periodic limits of this study is from pre-Qin to Tand. For gentleman's gardens in Tang dynasty at once got out of the noble's gardens which had imitated the imperial gardens until Tang, and became the origin of the gardens of the literati appearing in post-Tang dynasty. The major findings are as follows : First, in pre-Qin period, the origin of the seclusion culture is classified as the metaphysical seclusion of Taoism and the physical seclusion of Confucianism. Although Pu, Yuan, and Uou which could be said the first step of the chinese gardens were inquired, the clear relation between the seclusion and them is not found. Second, during Qin-Han dynasty, the role of the gardens, as the settings of the seclusion, are comparatively minor, too. But uan Kuang-Han's garden considerably escaped from that of pre-Qin in the aspect of function, and it has the characteristics of recreation. Third, during Wei-Chin and Liu dynasty, two types of the seclusions emerged. One is the small seclusion, and the other the Great Seclusion. Though, as formerly, the contemporary gardens did not escaped from the imperial gardens, Shi Chong's garden can be the setting of the Court Seclusion. But the seven Righteous in Bamboos' and Tao Yuan-Ming's settings of the seclusion were real natural environments rather than gardens. Forth, in Tang dynasty, in spite of relatively low status, Bai Ju-Yi's theory of the middle Seclusion enabled gentlemen to make seclusion in sinecures unlike the court Seclusion. The theoretical background of the Middle Seclusion was Zen Buddhism and the State Examinations System and Bai Ju-Yi's private social position also had an important effect on it. In Tang dynasty, there being nobiliary gentleman's gardens, Bai Ju-Yi's garden, Lushan Caotangyuan, was the setting of the Middle Seclusion. It can be called a real gentleman's garden, for it is simple and small unlike the imperial gardens or the nobiliary gentleman's gardens.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.3
• /
• pp.255-269
• /
• 2023

Surface water temperature of a bay (from the south to the north) increases in spring and summer, but decreases in autumn and winter. Due to shallow water depth, freshwater outflow, and weak current, the water temperature in the central to northern part of the bay is greatly affected by the land coast and air temperature, with large fluctuations. Water temperature variations are large in the north-east coast of the bay, but small in the south-west coast. The difference between water temperature and air temperature is greater in winter and in the south-central part of the bay than that in the north to the eastern coast of the bay where sea dykes are located. As the bay goes from south to north, the range of water temperature fluctuation and the phase show increases. When fresh water is released from the sea dike, the surrounding water temperature decreases and then rises, or rises and then falls. The first mode of empirical orthogonal function (EOF) represents seasonal variation of water temperature. The second mode represents the variability of water temperature gradient in east-west and north-south directions of the bay. In the first mode, the maximum and the minimum are shown in autumn and summer, respectively, consistent with seasonal distribution of surface water temperature variance. In the second mode, phases of the coast of Seosan~Boryeong and the east coast of Anmyeon Island are opposite to each other, bordering the center of the deep bay. Periodic fluctuation of the first mode time coefficient dominates in the one-day and half-day cycle. Its daily fluctuation pattern is similar to air temperature variation. Sea conditions and topographical characteristics excluding air temperature are factors contributing to the variation of the second mode time coefficient.

• Journal of the Korean association of regional geographers
• /
• v.2 no.2
• /
• pp.113-131
• /
• 1996

The purpose of this study is to identify the existence, personal characteristics and behavior of market-participants, and function of urban weekly markets in Taegu City through observation, interview and questionnaire survey. There are four weekly periodic markets such as Seongso(Monday), Chilgok(Wednesday), Siji(Thursday), and Chilgok(Friday) which have recently developed near the new apartment areas on the outskirts of Taegu. The major findings of this study can be summarized as follows: These markets originated from the agricultural cooperative's Friday markets, but were substantially established by mobile traders or merchants for the sake of their livelihood. Therefore, the existence of these markets is not explained by Stine's central place perspective but partially explained by Hay's economic locational and Bromley's socio-cultural perspective. Most traders are male, aged 30 to 40 years and have an educational level higher than high school. Most of them are living in Taegu and itinerantly visit more than two markets among the four markets by small truck. And most of them sell agricultural products and other food materials, except some who sell manufactured goods. Most consumers are housewives, aged 20 to 30 years and have an educational level higher than high school. Most of them are living within 1,000m and go there on foot. Most of them visit the markets around 3 to 5 p.m. on every market day. And they mostly buy vegetables, fruits, and fishes. Weekly markets provide employment opportunities for those who want to be merchants, and also contribute to the increase of farmers' income, because some traders(18.8%) are farmers who periodically visit markets to sell agricultural products. On the other hand, they function as a general food materials markets to neighboring residents. From these facts, both traders and consumers want weekly markets sustained. Therefore, these markets need to be protected by institutional assistance in spite of being informal markets.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.2 no.1
• /
• pp.109-131
• /
• 2007

The purpose of this study were to a) clarify the current practice of internal marketing by contracted food service management companies, b) analyze the effectiveness of current internal marketing practices. The survey was conducted between October 12 and November 2, 2002 with the 10 contracted food service management companies; 6 large, and 4 small & medium sized companies. No significant difference was existed with the categories of internal marketing. However significant differences were existed with the service education, sanitary education, periodic interviews, rewards for best employees, incentive payments, paid -leave allowances, job function allowances, and position classes including unit manager, dietician and cook of MBO. The actual administration of internal marketing strategies showed that, the significant differences were existed with education, paid-leave, and employee welfare systems among position classes. Also the significant differences were existed with all categories of internal marketing between large and small & medium sized companies. In general, small & medium sized companies score of the internal marketing performance was lower than that of large sized companies. Therefore, the segmented internal marketing strategies depending on the analysis not only demand for employees but also the size of company, were required to be an effectively and efficiently managed contracted food management companies.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.4
• /
• pp.335-341
• /
• 2015

In this study, we analyzed a two-dimensional Stokes flow through a microchannel containing projections with constant spacing attached to each wall. The projections on the top and bottom walls were semi-circular in shape, with in-phase locations. By considering the periodicity and symmetry of the flow, the eigenfunction expansion and least squared error method were applied to determine the stream function and pressure distribution. For some typical radius and spacing values, the streamline patterns and pressure distributions in the flow field are shown, and the shear stress distributions on the boundary walls are plotted. In addition, the average pressure gradients in the microchannel are also calculated and shown with the radius and spacing of the projections. In particular, the results for the case of extremely small gaps between the projections on the top and bottom walls are in good agreement with the lubrication results.

• Applied Microscopy
• /
• v.24 no.3
• /
• pp.10-22
• /
• 1994

To investigate the morphology of the synovial lining cells, synovitis was induced by carrageenin injection into the rat knee joint cavities. Synovial membranes were excised at 1, 3, 5, 7 and 14 days, and histologic, electron microscopic, histochemical (periodic acid Schiff: PAS, toluidine blue), and enzyme histochemical (acid phosphatase: ACP, nonspecific esterase: NSE and endogenous peroxidase) studies were performed. The results are as follows: Carrageenin induced synovial membrane hypertrophy with synovial cell proliferation and granuloma formation. The proliferated synovial lining cells and macrophages in the granulomatous lesion had round to oval nuclei and large, plump cytoplasm with many phagocytotic materials and vacuoles. Electron microscopically, these cells had small number of granular endoplasmic reticulum and many lysosomes, phagosomes and vaculoes. Mitotic figures were observed at early stage of experiment. PAS and toluidine blue stains showed strongly positive reaction in the cytoplasm of the proliferated lining cells and macrophages in granulomatous lesion. ACP and NSE activities were strong positive in the cytoplasm of the proliferated synovial lining cells and macrophages in the granulomatous lesion. But endogenous peroxidase stains were negative in all prolifeative lining cells and macrophages in granulomatous lesion. Conclusively, carrageenin-induced synovitis showed proliferation of synovial lining cells and granuloma formation in deep layer. The macrophages, which consisted of the lesions and have active phagocytic function, were speculated to proliferate by mitosis of superficial synovial A cells and histiocytes in the deep layer of the synovial membrane.

• Journal of Navigation and Port Research
• /
• v.47 no.6
• /
• pp.315-323
• /
• 2023

Marine accidents due to loss of stability of small ships have continued to increase over the past decade. In particular, since sudden winds have been pointed out as main causes of most small ship accidents, safety measures have been established to prevent them. In this regard, to prevent accidents caused by sudden winds, a systematic analysis technique is required. The aim of the present study was to develop a probabilistic approach to estimate extreme value and evaluate effects of wind on motion characteristics of ships. The present study included studies of motion analysis, extraction of extreme values, and motion characteristics. A series analysis was conducted for three conditions: wave only, wave with uniform wind speed, and wave with the NPD wind model. Hysteresis filtering and Peak-Valley filtering techniques were applied to time-domain motion analysis results for extreme value extraction. Using extracted extreme values, the goodness of fit test was performed on four distribution functions to select the optimal distribution-function that best expressed extreme values. Motion characteristics of a fishing boat were evaluated for three periodic motion conditions (Heave, Roll, and Pitch) and results were compared. Numerical analysis was performed using a commercial solver, ANSYS-AQWA.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.6
• /
• pp.584-591
• /
• 2020

Reliability is an important factor in weapons systems. Low reliability causes the weapons system to fail to function properly, which directly leads to the weakening of combat capability. This paper classifies the structure of the 5.56 mm rifle, which is currently used by the Korean army, into a total of seven assemblies and describes the eight functions necessary for the rifle to operate normally. In addition, the concept of reliability was defined as the MRBF, and the Poisson process model and TTT plot were explained as a reliability analysis theory for the repair function system. Next, the field-data obtained by defining failure as the replacement of parts other than periodic exchange of parts were refined, and the reliability was analyzed by entering the refined field operation specifications into the Minitab program. As a result, the reliability of the rifle was determined to be 251.73. The assembly parts that required improvement was identified as the barrel, lower body, and butt stock assembly, and 10 detailed parts needed to be improved. Finally, the limits of the reliability analysis using the field-data currently available for small caliber firearms were considered.

• Journal of the Korean Geographical Society
• /
• v.30 no.3
• /
• pp.269-295
• /
• 1995

This research is concerned with the social division of labor within the traditional industry district: Damyang bamboo ware industry district and Yeoju pottery industry district in South Korea, Damyang bamboo ware and Yeoju pottery are well known of the Korean traditional industry. The social division of labor in an industry district is considered as an important factor. The social division of labor helps the traditional industry to survive today. This summary shows five significant points from the major findings. First, Damyang bamoo ware industry and Yoeju pottery industry have experienced the growth stages until 1945, the stagnation in the 1960s, and the business recovery in the 1980s. Most Korean traditional industries had been radically declined under the Japanese colonization; while, Damyang bamboo ware industry and Yeoju pottery industry district have been developed during above all stages. The extended market to Japan helped the local government to establish a training center, and to provide financial aids and technical aids to crafts men. During the 1960s and 1970s, mass production of substitute goods on factory system resulted in the decrease of demand of bamboo ware and pettery. During the 1980s, these industries have slowly recovered as a result of the increased income per capita. The high rate of economic growth in the 1960s and 1970s was playing an important role in the emerging the incleased demand of the bamboo ware and pottery. Second the production-and-marketing system in a traditional industry district became diversified to adjust the demand of products. In Damyang bamboo ware industry district, the level of social division of labor was low until the high economic development period. Bamboo ware were made by a farmer in a small domestic system, The bamboo goods were mainly sold in the periodic market of bamboo ware in Damyang. In the recession period in the 1960s and 1970s, the production-and-marketing system were diversified; a manufacturing-wholesale type business and small-factory type business became established; and the wholesale business and the export traders in the district appeared. In the recovery period in the 1980s, the production-and-marketing systems were more diversified; a small-factory type business started to depend On subcontractors for a part of process of production; and a wholesale business in the district engaged in production of bamboo ware. In Yeoju pottery industry district, the social division of labor was limited until the early 1970s. A pottery was made by a crafts man in a small-business of domestic system and sold by a middle man out of Yeoju. Since the late 1970s, production-and-marketing system become being diversified as a result of the increased demand in Japan and South Korea. In the 1970s, Korean traditional craft pottery was highiy demanded in Japan. The demand encouraged people in Yoeju to become craftsmen and/or to work in the pottery related occupation. In South Korea, the rapid economic growth resulted in incline to pottery due to the development of stainless and plastic bowls and dishes. The production facilities were modernized to provide pottery at the reasonable price. A small-busineas of domestic system was transformed into a small-factory type business. The social division of labor was intensified in the pottery production-and-maketing system. The manufacturing kaoline began to be seperated from the production process of pottery. Within the district, a pottery wholesale business and a retail business started to be established in the 1980s. Third the traditional industry district was divided into "completed one" and "not-completed one" according to whether or not the district firms led the function of the social division of labor. The Damyang bamboo ware industry district is "completed one": the firm within the district is in charge of the supply of raw material, the production and the marketing. In the Damyang bamboo ware district, the social division of labor w and reorganized labor system to improve the external economics effect through intensifying the social division of labor. Lastly, the social division of labor was playing an important role in the development of traditional industry districts. The subdivision of production process and the diversification of business reduced the production cost and overcame the labor shortage through hiring low-waged workers such as family members, the old people and housewives. An enterpriser with small amount of capital easily joined into the business. The risk from business recession were dispersed. The accumulated know-how in the production and maketing provided flexiblility to produce various goods and to extend the life-cycly of a product.d the life-cycly of a product.