• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1C
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• pp.33-42
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• 2006

Lots of river embankments or levees in Korea are quite so old and unknown the origin even. The river deposits, moreover, obtainable easily somewhere were used for materials of embankment without any technical considerations such as the influence soil properties and construction methods on embankment stability. It's natural that safety would be threatened if the water level rises due to flood or rainfall when it comes to abnormal weather conditions, especially. From this point of view, enlargement of embankment, irrigation works, etc. are in progress recently at the situation from a reinforcement work. However, taking influence of soil properties and construction methods on embankment stability into account against cracking or piping is still insufficient. Fragmentary design criteria or irrational construction methods are applied rather as the case may be. In this study, therefore, a way to estimate piping and cracking resistance (Sherard, 1953) has been introduced and reevaluated for practical use with an eye to material properties and its applicability to piping-experienced embankments was examined. Piping possibility was also examined in the present design criteria and compared. In view of the results achieved, it reflects that both yield piping possibility. But it's still necessary to complement how to judge and verify piping resistance of given soils with gradation curves by the representative curve, quantitatively and that piping resistance should consider compaction effects as well.

• Progress in Medical Physics
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• v.25 no.2
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• pp.100-109
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• 2014

In stereotactic body radiotherapy (SBRT), the accurate location of treatment sites should be guaranteed from the respiratory motions of patients. Lots of studies on this topic have been conducted. In this letter, a new verification method simulating the real respiratory motion of heterogenous treatment regions was proposed to investigate the accuracy of lung SBRT for Volumetric Modulated Arc Therapy. Based on the CT images of lung cancer patients, lung phantoms were fabricated to equip in $QUASAR^{TM}$ respiratory moving phantom using 3D printer. The phantom was bisected in order to measure 2D dose distributions by the insertion of EBT3 film. To ensure the dose calculation accuracy in heterogeneous condition, The homogeneous plastic phantom were also utilized. Two dose algorithms; Analytical Anisotropic Algorithm (AAA) and AcurosXB (AXB) were applied in plan dose calculation processes. In order to evaluate the accuracy of treatments under respiratory motion, we analyzed the gamma index between the plan dose and film dose measured under various moving conditions; static and moving target with or without gating. The CT number of GTV region was 78 HU for real patient and 92 HU for the homemade lung phantom. The gamma pass rates with 3%/3 mm criteria between the plan dose calculated by AAA algorithm and the film doses measured in heterogeneous lung phantom under gated and no gated beam delivery with respiratory motion were 88% and 78%. In static case, 95% of gamma pass rate was presented. In the all cases of homogeneous phantom, the gamma pass rates were more than 99%. Applied AcurosXB algorithm, for heterogeneous phantom, more than 98% and for homogeneous phantom, more than 99% of gamma pass rates were achieved. Since the respiratory amplitude was relatively small and the breath pattern had the longer exhale phase than inhale, the gamma pass rates in 3%/3 mm criteria didn't make any significant difference for various motion conditions. In this study, the new phantom model of 4D dose distribution verification using patient-specific lung phantoms moving in real breathing patterns was successfully implemented. It was also evaluated that the model provides the capability to verify dose distributions delivered in the more realistic condition and also the accuracy of dose calculation.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.2
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• pp.26-35
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• 2009

This study is an analysis of the design changes of children's play facilities and the related rules and regulations which causes these changes. Accordingly, it is noticed that a site's change of design by legislation and by yearly alternation influences playground design. First, after revising the provisions for the distance from roads and parking lots, the constructing of safety fences between play facilities and the using of durable materials, alterations of the designs have been made a reality. Second, the design changes after the period of regulation transitions were caused by provisions related to the shelter of evergreens and conditions of the sun. Third, the changes of the playgrounds were related to the substitution of exercise facilities for the local residents and in carrying out a hygiene exam more than twice a year. Because a lack of regulatory standards for the design of playgrounds resulted in compliance based on individual interpretation and because a substitution of exercise facilities is part of the way to alleviate these regulations, the conditions of the site under investigation could be projeced. By such changes of regulations and analysis of alterations of playground design, programs for improvement were suggested. It turned out that the composition of the concrete standard in conformity with regulations required closer observance. Moreover, design standards for children's playgrounds are needed, such as the provision of variation in external appearance, the creation of more flexible layouts and the outlining of spaces by themes.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.1
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• pp.49-60
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• 2008

Objective: This study was carried out to investigate the effects of 3-dimensional co-culture of human endometrial cells decidualized with progesterone and TGF-${\beta}1$ on the development of 2-cell mouse embryos. Methods: Stromal and epithelial cells isolated from human endometrial tissue were immunostained for cytokeratin and vimentin. Expression of TGF-${\beta}1$, its receptor-1, -2, integrin-${\beta}3$ and prolactin in mono or co-culture according to three different hormone conditions was investigated by RT-PCR. Differential staining was used to investigate the number of ICM and trophectoderm of hatched mouse blastocysts in different three conditions. Results: The immunohistochemical study was positive for cytokeratin or vimentin and confirmed that epithelial and stromal cells were isolated from endometrial tissue successfully. In co-culture, TGF-${\beta}1$, its receptor-1, integrin-${\beta}3$ and prolactin except TGF-${\beta}1$-r2 were expressed in progesterone dominant condition. The hatching and attaching rate were higher in the co-culture with decidualized cells (p<0.05). However, we observed that lots of the incomplete hatched blactocysts attached on non-decidualized cells. The ICM number of hatched mouse blastocysts was higher in co-culture with decidualized and non decidualized cells than media only culture (p<0.05). The trophectoderm number of hatched blastocyst was higher in the co-culture with decidualized cells than non-decidualized cells or media only culture (p<0.05). Conclusion: The administration of progesterone, estrogen and TGF-$\beta$ could induce decidualization of stromal and epithelial cells isolated from human endometrial tissue using 3-dimensional co-culture, and the decidualization of human endometrial cells could increase the hatching and attaching rate of 2-cell mouse embryos.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.8
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• pp.420-427
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• 2016

This study was conducted on the sediment remediation using micro-bubble to remove fine particles. For this study, characteristics of contamination and release in sediment were analyzed. And then, the characteristics of bubbles on removal efficiency was investigated at various operation conditions. In particle size distribution of the sediment used for the study, the proportion of clay and silt (<0.075 mm) was about 7.7%, sand (0.075~4.75 mm) was about 67.8%, and gravel (${\geq}4.75$) was 24.5%. Total nitrogen (TN) and total phosphorus (TP) of the sediment were 2,790~3,260, 261~311 mg/kg respectively. Ignition loss and water content were 4.1~9.6, 32.9~53.2% respectively. In analysis of removal efficiency according to operation conditions of micro-bubble, it was the highest when operation condition is pressure 6 atm, pressurized water ratio 30%, and coagulant dosage 15 ppm. At the time, the sediment's removal efficiency was 19.9%. Accordingly removal efficiency of TN and TP were 21.4, 22.6% respectively. Finally a research was found that fine particles in sediment were almost removed by micro-bubble, which led to decrease nutrients' release at about 20.1~64.3% in comparison to sediment including lots of fine particles.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.s02
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• pp.45-65
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• 1989

The Korean peninsular having the complexity of the photography and variability of climate is located within passing area of a lots of typhoon occurring from the southern islands of Philippines. So, there are various patterns of wind and flooding damages in paddy field occuring by the strong wind and the heavy rain concentrated during the summer season of rice growing period in Korea. The wind damages to rice plants in Korea were mainly caused by saline wind, dry wind and strong wind when typhoon occurred. The saline wind damage having symptom of white head or dried leaves occurred by 1.1 to 17.2 mg of salt per dry weight stuck on the plant which was located at 2. 5km away from seashore of southern coastal area during the period(from 27th to 29th, August, 1986) of typhoon &Vera& accompanying 62-96％ of relative humidity, more than 6 m per second of wind velocity and 22.5 to 26.4$^{\circ}C$ of air temperature without rain. Most of the typhoons accompanying 4.0 to 8. 5m per second of wind and low humidity (lesp an 60％) with high temperature in the east coastal area and southen area of Korea. were changed to dry and hot wind by the foehn phenomenon. The dry wind damages with the symptom of the white head or the discolored brownish grain occurred at the rice heading stage. The strong wind caused the severe damages such as the broken leaves, cut-leaves and dried leaves before heading stage, lodging and shattering of grain at ripening stage mechanically during typhoon. To reduce the wind damages to rice plant, cultivation of resistant varieties to wind damages such as Sangpoongbyeo and Cheongcheongbyeo and the escape of heading stage during period of typhoon by accelerating of heading within 15th, August are effective. Though the flood disasters to rice plant such as earring away of field, burying of field, submerging and lodging damage are getting low by the construction of dam for multiple purpose and river bank, they are occasionally occurred by the regional heavy rain and water filled out in bank around the river. Paddy field were submerged for 2 to 4 days when typhoon and heavy rain occurred about the end of August. At this time, the rice plants that was in younger growing stage in the late transplanting field of southern area of Korea had the severe damages. Although panicles of rice plant which was in the meiotic growing stage and heading stage were died when flooded, they had 66％ of yield compensating ability by the upper tilling panicle produced from tiller with dead panicle in ordinary transplanting paddy field. It is effective for reduction of flooding damages to cultivate the resistant variety to flooding having the resistance to bacterial leaf blight, lodging and small brown planthopper simultaneously. Especially, Tongil type rice varieties are relatively resistant to flooding, compared to Japonica rice varieties. Tongil type rice varieties had high survivals, low elongation ability of leaf sheath and blade, high recovering ability by the high root activity and photosynthesis and high yield compensating ability by the upper tillering panicle when flooded. To minimize the flooding and wind damage to rice plants in future, following research have to be carried out; 1. Data analysis by telemetering and computerization of climate, actual conditions and growing diagnosis of crops damaged by disasters. 2. Development of tolerant varieties to poor natural conditions related to flooding and wind damages. 3. Improvement of the reasonable cropping system by introduction of other crops compensating the loss of the damaged rice. 4. Increament of utilization of rice plant which was damaged.

• Journal of Distribution Research
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• v.17 no.5
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• pp.129-146
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• 2012

Recently, Korea became the 7th country in the world which has got into the 20-50 clubs that means the population is 50 million and per capital income is $20,000. From the view point of the retail industry, it suggests that Korea should have its own self-sufficient market by itself. With abundant labor and increased disposable income, it made the consumer's needs change. Responding to the change, retail and F&B oriented retail malls are now starting to add culture, art and entertainment facilities in the configurations. Such complexity and variety of the shopping malls became trendy and many shopping complexes are scheduled to open in the near future across the country. Due to above reasons, it became the common trend to develop shopping complex all over the cities now. However, the history of the shopping mall in Korea is much shorter than developed countries such as America and Japan. Thereby, a lot of problems, trial and error have occurred in the process of developing and operating them. If development of shopping complex failed, it would return lots of damages to the stakeholder. Therefore, the corporations should develop the mall properly and government might support positively. In this study, we would like to propose on how all the mall should be developed and well managed and what are the ways for the vitalizing factors of the shopping complex after benchmarking other shopping mall cases. Through the case study, we realized that the most crucial factors for vitalizing shopping complex were interior design, merchandising and how well they operate the mall. In case of the failed shopping mall, developers sell each store to individual proprietors and never take care of them after they get the profit, which make it hard to have integrated marketing strategies. That causes the overall slump of the mall. Corporations developing the mall should operate it as well, so that it could be possible to make the mall consistently well managed and promoted. There is a certificate for the shopping mall expert in The States and Japan. However, we do not have this kind of certificate. In fact, if we judge the capability of a person who is involved in the shopping mall industry, we usually measure how many years they stick to the same industries and that is not equally the same as their competence. Therefore it is necessary to organize "Shopping Mall Associate" and introduce shopping mall license for the mall expert. Due to retail trends, we can easily see a lot of shopping facilities all over the cities but not every mall is able to be successful. We think it's essential that the government should certify the malls which are qualified for the design, merchandising and proficiency of the operation. For the qualified mall, the government could confer a benefit on the company such as reducing corporation taxes. In multi-complex shopping mall it is possible to make convenient for customers. However, if a mall failed to succeed, it would be disaster. To build a shopping complex, developers should invest huge money even take out loan so that many people would be connected to the project, which may affect their whole financial conditions. In addition, only qualified corporation should develop and operate shopping complex and the government must support and aid the developers in order to make a better shopping environment in which customers might be happy during their shopping experience.

• Cartoon and Animation Studies
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• s.6
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• pp.152-171
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• 2002

This study analyses the avatar service, which is recognized as an alternative strategy of animation industry. The research questions of this study are following: (1) How have the avatar services been developed and what are the present dominant types? (2) Which structural characteristics of e-business environment are needed for the success of avatar services? (3) What is the economic characteristics of avatar business model? To solve these research questions, the basic conditions and the structural characteristics of avatar services have been investigated. In the first place, two forms of avatar service are classified. One is the internet service site whole primary service is to provide chatting service based on avatar service. The other is the portal site in which many kinds of products and services are presented as bundles to meet the needs of internet users. So avatar service is one of bundles which those portal sites are providing with. In this study, the big five internet service sites are selected based on the profits they earned through the sales of avatar service. The result of analysis is that the pricing strategy of those big five sites is very different from those of traditional off-line markets. The pricing mechanism are based on the value which internet users endow with the avatar items, not based on the costs of making the products. Avatar is the representative informative goods. The informative goods have the original cost structures, constant fixed costs and zero marginal costs, so the providers of avatar services make much of the subjective values of consumers. The sayclub, which is the most successful avatar service site and earn the average sales of 3 billing won a month, takes the aggressive strategy of pricing avatar items at highest price in the industry. The avatar service providers which make lots of profits are planning of making differentiate the services, introducing well-known brand items and star-named items. Nevertheless, the fact that the members of the sayclub are not decreasing means that the network effect of the site is so strongly manifest. Moreover, the costs the members have paid for the avatar items are so big not as to switch from one site to the other site, it can be very costly. These switching costs are endemic in high-technology industries and digital contents industries. It can be so large that switching suppliers is virtually unthinkable, a situation known as 'lock-in'. When switching costs are substantial, competition can be intense to attract new customers, since, one they are locked in, they can be a substantial source of profit. The consumers of avatar items have switching costs if they subscribe for the new avatar service site. The switching costs can be subscription costs as well as the costs of giving up the items they already paid for. One common example of switching costs involves specialized supplies, as with inkjet printer cartridges. In this example, the switching cost is the purchase of a new printer. The market is competitive ex ante, but since cartridges are incompatible, it is monopolized dx post. So the providers of printer/cartridges set pricing printer so cheap and cartridges expensive. On the contrary, since the avatar service can be successful with the strong network effect, the providers of avatar services have to compete aggressively for new customers. So they allow the subscription at a low price(almost marginal cost) in the early market. The network effect can be maximized when the members are sufficiently growing. The providers which have the monopoly power with sufficient subscribers. begin to raise the prices over the lifetime of the product and make profits.

• Journal of Oral Medicine and Pain
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• v.38 no.2
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• pp.121-136
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• 2013

It has been known that saliva may affect the most of oral diseases. On the contrary, several systemic conditions may affect salivary flow and cause oral dryness and psychosocial stress especially may a crucial role in the etiology of hyposalivation and oral dryness. Many studies have focused on macroscopic effects of the stress on the salivary glands by autonomic response, but on the other hand it has hardly been reported on cellular microscopic effects of the stress on the salivary glands. Therefore, this study was performed to examine clusterin, a antiapoptotic and cytoprotective protein, in the parotid glands under restraint stress condition. For this study, 18 rats were divided into 3 groups; 1) 2 rats of group I were selected as a normal control. 2) 2 rats of group II, as a experimental control were placed in the restraint cone for 2 hours 3) 14 rats of group III were placed in the restraint cone for 2 hours once a day. The rats were sacrificed immediately(group II, as a experimental control), 1, 2, 3, 4, 5, 6 and 7 days after application of the stress and the both parotid glands were excised. Immunohistochemistry and electron microscopy were performed. The finding were as follows: 1. In parotid glands, repeated stress denaturalize the acinar cells, interacinous tissues and interacinous connective tissues were separated to individual acinar cells. After 4 days of experiment, there were lots of vacuoles and intercalated ducts. 2. In parotid glands, repeated stress make the rER which is in acinar cells swollen after 3 days of experiment and it was intensified to 4 days. After 5 days of experiment the edema got worse and degenerated. 3. In parotid glands, clusterin was reduced in ductal cell cytoplasm but in intercalated duct clusterin was slightly stained until 3 days prominently increased until 4 days and then decreased again after 5 days of experiment.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.12
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• pp.1098-1125
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• 2000

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 1998 and 1999 has been done. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environment. The conclusions are as follows. 1) A review of the recent studies on fluid flow, turbomachinery and pipe-network shows that many experimental investigations are conducted in applications of impingement jets. Researches on turbulent flows, pipe flows, pipe-networks are focused on analyses of practical systems and prediction of system performance. The results of noise reduction in the turbomachinery are also reported. 2) A review of the recent studies on heat transfer analysis and heat exchanger shows that there were many papers on the channel flow with the application to the design of heat exchanger in the heat transfer analysis. Various experimental and numerical papers on heat exchanger were also published, however, there were few papers available for the analysis of whole system including heat exchanger. 3) A review of the recent studies on heat pump system have focused on the multi-type system and the heat pump cycle to utilize treated sewage as the heat source. The defrosting and the frosting behaviors in the fin-tube heat exchanger is experimentally examined by several authors. Several papers on the ice storage cooling system are presented to show the dynamic simulation program and optimal operation conditions. The study on the micro heat pipes for the cooling of high power electronic components is carried out to examine the characteristics of heat and mass transfer processed. In addition to these, new type of separate thermosyphon is studied experimentally. 4) The recent studies on refrigeration/air conditioning system have focused on the system performance and efficiency for new alternative refrigerants. New systems operating with natural refrigerants are drawing lots of attention. In addition to these, evaporation and condensation heat transfer characteristics of traditional and new refrigerants are investigated for plain tubes and also for microfin tubes. Capillary tubes and orifice are main topics of research as expansion devices and studies on thermophysical properties of new refrigerants and refrigerant/oil mixtures are widely carried out. 5) A review of the recent studies on absorption cooling system shows that numerous experimental and analytical studies on the improvement of absorber performance have been presented. Dynamic analysis of compressor have been performed to understand its vibration characteristics. However research works on tow-phase flow and heat transfer, which could be encountered in the refrigeration system and various phase-change heat exchanger, were seemed to be insufficient. 6) A review of recent studies on duct system shows that the methods for circuit analysis, and flow balancing have been presented. Researches on ventilation are focused on the measurement of ventilation efficiency, and variation of ventilation efficiency with ventilation methods by numerous experimental and numerical studies. Furthermore, many studies have been conducted in real building in order to estimate indoor thermal environments. Many research works to get some information for cooling tower design have been performed but are insufficient. 7) A review on the recent studies on architectural thermal environment and building mechanical systems design shows that thermal comfort analysis is sitting environment, thermal performance analysis of Korean traditional building structures., and evaluation of building environmental load have been performed. However research works to improve the performance of mechanical system design and construction technology were seemed to be insufficient.