• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.3
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• pp.265-276
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• 1995

In this Paper, the Performance of the convolution method has been investigated as an effort to develop a simple system of predicting wind-driven surface current on a real time basis. In this approach wind stress is assumed to be spatially uniform and the effect of atmospheric pressure is neglected. The discrete convolution weights are determined in advance at each point using a linear three-dimensional Galerkin model with linear shape functions(Galerkin-FEM model). Four directions of wind stress(e.g. NE, SW, NW, SE) with unit magnitude are imposed in the model calculation for the construction of data base for convolution weights. Given the time history of wind stress, it is then possible to predict with-driven currents promptly using the convolution product of finite length. An unsteady wind stress of arbitrary form can be approximated by a series of wind pulses with magnitude of 6 hour averaged value. A total of 12 pulses are involved in the convolution product To examine the accuracy of the convolution method a series of numerical experiments has been carried out in the idealized basin representing the scale of the Yellow Sea and the East China Sea. The wind stress imposed varies sinusoidally in time. It was found that the predicted surface currents and elevation fields were in good agreement with the results computed by the direct integration of the Galerkin model. A model with grid 1/8$^{\circ}$ in latitude, l/6$^{\circ}$ in longitude was established which covers the entire region of the Yellow Sea and the East China Sea. The numerical prediction in terms of the convolution product has been carried out with particular attention on the formation of upwind flow in the middle of the Yellow Sea by northerly wind.

• Journal of Periodontal and Implant Science
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• v.32 no.3
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• pp.539-554
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• 2002

It has been approximately 40 years since $Br{{\aa}}nemark$ first introduced osseo-integration for implants in the early 1960s. Unlike crown and bridge or denture treatment, implant treatment helps preserve existing bone and improve masticatory functions. Thus, the awareness of implant treatment has grown rapidly among dentists and patients alike in Korea, as it becomes a widely accepted treatment. The following results on patients type and implant distribution were compiled from 1814 implant cases of 640 patients treated at the periodontal dept. of Y University Hospital during 1992 to 2001. 1. There are no dissimilarities between men and women, with patients in their 40,50s accounting for 49% of patients and 56% of implant treatments; the largest share of patients and implant treatments. 2. Mn. posterior area accounted for 59% of implant treatments followed by Mx. posterior area(21%), Mx anterior area(l4%) and Mn anterior area 2%. 3. Partial edentulous patients treated by single crown and bridge-type prosthesis accounted for 98% and fully edentulous patient accounted for the remaining 2% 4. The major cause of tooth loss is periodontal disease, followed by dental caries, trauma and congenital missing. Compared to women, men are more likely to suffer from tooth loss due to periodontal disease. Also, older people are more likely to suffer from tooth loss due to periodontal disease rather than dental caries. 5. The distribution of bone quality for maxillae was 52% for type III, followed by 23% for type II, 20% for type IV and 0% for type I. As for mandible, the distribution was 52% for type II, followed by 37% for type III, 7% for type IV and 4% for type I. 6. The distribution of bone quantity for maxillae was 49% for type C, followed by 34% for type B, 14% for type D, 3% for type A, and 0% for type E. As for mandible, the distribution was 52% for type B, followed by 35% for type C, 6% for type D, 3% for type A and 0% for type E. 7. The majority of implants were those of 10-14mm in length (80%) and regular diameter in width (79%). The results provided us with basic data on patient type, implant distribution, bone condition, etc. We wish that our results coupled with other research data helps assist in the further study for better implant success/survival rates, etc.

• Journal of the Korean Regional Science Association
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• v.34 no.1
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• pp.31-47
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• 2018

This study examines the locational characteristics and change of business type in the residental areas that have commercial gentrification issues in Seoul, Korea, using the logistic regression model. The analysis results indicate that the gentrification occurrence areas are strongly associated with low-density and old residential areas. In addition, those areas are more likely to have great accessibilities to highway ramp, subway station, colleges, and other facilities that attract people. Regarding the characteristics of the road, gentrification occurrence areas are associated with longer road length, lower rate of road areas, higher local integration of road network, and higher rate of three-way intersections. This finding indicates that low-density and old residential areas with organic road networks have strong links with commercial gentrification. This study also finds that the business type has been substantially changed from 2006 to 2014 in the commercially gentrified residential areas. While the coffee shops and drinking places have been increased, but neighborhood-living facilities have been decreased. This study also shows that the business life-cycles of drinking places or Korean restaurant are getting short. Finally, this study discusses the commercial gentrification issues and policy implications in the residential districts in Seoul, Korea.

• Journal of the Korea Society of Computer and Information
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• v.16 no.6
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• pp.1-10
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• 2011

In designing multi-core processors, interconnection delay is one of the major constraints in performance improvement. To solve this problem, the 3-dimensional integration technology has been adopted in designing multi-core processors. The 3D multi-core architecture can reduce the physical wire length by stacking cores vertically, leading to reduced interconnection delay and reduced power consumption. However, the power density of 3D multi-core architecture is increased significantly compared to the traditional 2D multi-core architecture, resulting in the increased temperature of the processor. In this paper, the floorplan methods which change the forms of vertical placement of the core and the level-2 cache are analyzed to solve the thermal problems in 3D multi-core processors. According to the experimental results, it is an effective way to reduce the temperature in the processor that the core and the level-2 cache are stacked adjacently. Compared to the floorplan where cores are stacked adjacently to each other, the floorplan where the core is stacked adjacently to the level-2 cache can reduce the temperature by 22% in the case of 4-layers, and by 13% in the case of 2-layers.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.531-554
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• 2006

Oral implants must fulfill certain criteria arising from special demands of function, which include biocompatibility, adequate mechanical strength, optimum soft and hard tissue integration, and transmission of functional forces to bone within physiological limits. And one of the critical elements influencing the long-term uncompromise functioning of oral implants is load distribution at the implant- bone interface, Factors that affect the load transfer at the bone-implant interface include the type of loading, material properties of the implant and prosthesis, implant geometry, surface structure, quality and quantity of the surrounding bone, and nature of the bone-implant interface. To understand the biomechanical behavior of dental implants, validation of stress and strain measurements is required. The finite element analysis (FEA) has been applied to the dental implant field to predict stress distribution patterns in the implant-bone interface by comparison of various implant designs. This method offers the advantage of solving complex structural problems by dividing them into smaller and simpler interrelated sections by using mathematical techniques. The purpose of this study was to evaluate the stresses induced around the implants in bone using FEA, A 3D FEA computer software (SOLIDWORKS 2004, DASSO SYSTEM, France) was used for the analysis of clinical simulations. Two types (external and internal) of implants of 4.1 mm diameter, 12.0 mm length were buried in 4 types of bone modeled. Vertical and oblique forces of lOON were applied on the center of the abutment, and the values of von Mises equivalent stress at the implant-bone interface were computed. The results showed that von Mises stresses at the marginal. bone were higher under oblique load than under vertical load, and the stresses were higher at the lingual marginal bone than at the buccal marginal bone under oblique load. Under vertical and oblique load, the stress in type I, II, III bone was found to be the highest at the marginal bone and the lowest at the bone around apical portions of implant. Higher stresses occurred at the top of the crestal region and lower stresses occurred near the tip of the implant with greater thickness of the cortical shell while high stresses surrounded the fixture apex for type N. The stresses in the crestal region were higher in Model 2 than in Model 1, the stresses near the tip of the implant were higher in Model 1 than Model 2, and Model 2 showed more effective stress distribution than Model.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.4
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• pp.361-369
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• 2008

The purpose of this study is to make porous oxide film on the surfaces of pure Ti through anodic spark discharge in electrolytic solution containing calcium and phosphate ions, to improve osseointergration by treating fluoride agent. In addition, it is to evaluate the fluoride modified effect on the surface. Commercial pure Ti plate with $20{\times}10{\times}2mm$ and Ti wire with a diameter of 1.5mm and a total length of 15mm were used. After making titanium oxide films converted by anodic spark discharge, anodizing was performed. Fluoride was spreaded to titanium laboratory plate and maintained for 30 minutes after anodizing breakdown. Fluoride ion discharge amount was measured per 24 hours after dipping titanium plate into saline (10ml) and sustaining 90rpm in a pyrostat. Some plates and wires were dipped in Hanks solutions for a month to examine biocompatibility using SEM and XRD. $TiO_2$ film formed by anodic discharge technique showed great roughness and uniform pores which were $1{\sim}3{\mu}m$ in a diameter. Roughness of the films treated with anodic discharge after blasting were higher than the turned ones(P<0.05). Rapid surface activity was observed in the samples treated with $TiF_3$ agent, which immersed in Hanks solution for 30 days. Taking the results into consideration, the fluoride modified implant with anodic discharge demonstrates that it makes uniformly porous oxide film on the surface of implant and properly increase roughness for osseointegration. The implants will achieve greater bone integration after short healing time by improving surface activity.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.43 no.1
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• pp.49-61
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• 2007

Otter boards in the trawl are the one of essential equipments for the net mouth to be spread to the horizontal direction. Its performance should be considered in the light of the spreading force to the drag and the stability of towing in the water. Up to the present, studies of the otter boards have focused mainly on the drag and lift force, but not on the stability of otter boards movement in 3 dimensional space. In this study, the otter board is regarded as a rigid body, which has six degrees of freedom motion in three dimensional coordinate system. The forces acting on the otter boards are the underwater weight, the resistance of drag and spread forces and the tension on the warps and otter pendants. The equations of forces were derived and substituted into the governing equations of 6 degrees of freedom motion, then the second order of differential equations to the otter boards were established. For the stable numerical integration of this system, Backward Euler one of implicit methods was used. From the results of the numerical calculation, graphic simulation was carried out. The simulations were conducted for 3 types of otter boards having same area with different aspect ratio(${\lambda}=0.5,\;1.0,\;1.5$). The tested gear was mid-water trawl and the towing speed was 4k't. The length of warp was 350m and all conditions were same to each otter board. The results of this study are like this; First, the otter boards of ${\lambda}=1.0$ showed the longest spread distance, and the ${\lambda}=0.5$ showed the shorted spread distance. Second, the otter boards of ${\lambda}=1.0$ and 1.5 showed the upright at the towing speed of 4k't, but the one of ${\lambda}=0.5$ heeled outside. Third, the yawing angles of three otter boards were similar after 100 seconds with the small oscillation. Fourth, it was revealed that the net height and width are affected by the characteristics of otter boards such as the lift coefficient.

• Korea journal of population studies
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• v.11 no.1
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• pp.14-31
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• 1988

The national family planning program in Korea, which was instituted as an integral part of the nation's economic development plans since 1962, has contributed greatly to a reduction in the fertility and population growth rate. The total fertility rate dipped from 6.0 births per women in 1960 to 2.0 in 1985, and the population growth rate rom 2.84 percent per year to 1.25 percent during the same period, while the contraceptive practice rate for the 15-44 married women increased from 9 percent in 1965 to 70 percent in 1985. Study findings indicate that the fertility reduction in the past 26 years is largely attributed to the virgorous implementation of the national family planning program, rising age at marriage, wide-spread use of induced abortion, and the changes in attitude regarding the value of children that came into being in the wake of the rapid socio-economic development over the period. Among the strengths of the national family planning program are the following : 1) a pluralistic system of program manageent with active participation of various government and voluntary organizations, 2) utilization of a large corps of family planning field workers to conduct face-to-face communication and motivation activities, 3) use of private physicians with government support to provide contraceptive services, 4) a systematic program management system including program planning of traget allocation, evaluation, and supervision with a broad MIS and award system, 5) numerous incentive and disincentive schemes for stimulating the small family norm and contraceptive use, and 6) strong commitments to the family planning program by political leaders. The new demographic targets during the Sixth Five-Year Economic and Social Development plan period(1987-91) have been set for a further reduction in the population growth rate to 1.0 percent by 1993, assuming that the TFR will decline to 1.75 level in 1995. This target is, however, not easy to achieve due to anticipated unfavorable factors like the strong boy preference, high discontinuation rates of reversible contraceptive methods, fertility termination-oriented contraceptive use, a plateau level of contraceptive practice rate that has mostly accounted for a sterilization, shortened length of birth intervals, and the changing patterns of contraceptive mix. The recent changes in contraceptive and fertility behaviors clearly indicate that the past quantity-oriented management system of the national program should be redirected toward a quality-oriented approach. Particularly, program efforts should be expanded to recruit new contraceptive users in the 20s of younger age groups, both for birth spacing and controlling their fertility since the women aged 20 to 29 account for more than 80 percent of the total annual births in recent years. In addition, the current contraceptive fee system of the national family planning program should be gradually shifted from free contraceptive services to a acceptor's charge system, and the provision of contraceptive services through the medical insurance system, which will cover the entire population by 1989, should be accelerated as a means of integration of family planning program with other health programs.

• Journal of the Korean Institute of Gas
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• v.25 no.5
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• pp.78-87
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• 2021

This paper analyzes the range and attributes of the traffic information service between domestic public institutions and private companies, and suggests the possibility of joint application of node-link information for each company and the possibility of joint use of private traffic information. For this purpose, the present condition and attributes of domestic and foreign traffic information node-links (link length, node ID number, U-turn information, lane information, left turn information, right turn information, etc.) were analyzed. The analysis targets, the node-link of the national standard node and the two companies were analyzed. The area of the experiment was selected in Jongno-gu, Seoul, where standard-link information is complex, traffic volume is high, and various standard-links exist. The experiment was conducted by comparing and analyzing the traffic information attributes of three types of node-links and performing node-links overlapping matching (utilizing encoding_decoding method), and the possibility of matching node-links and attributes of different specifications was analyzed using Open LR technique.

• Iberoamérica
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• v.22 no.2
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• pp.25-57
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• 2020

Eduardo Galeano is a left-wing intellectual who led the criticism and accusations of dictatorship and social absurdity in Latin America. It digs into the truth of hidden history that has not been revealed in official history. He values the memory of history to stop repetition of the unfortunate history of the past. The main research topic of this study, 『The Book of Embraces』, is also an extension of such work. Most of the stories in this work depend on the writer's memory. There is no coherence or integration in the content of the story, and the length of the text is not constant, so it is extremely informal and fragmented. This is a strategy to formally reveal the illogical and irrational reality of Latin America. He analyzes the problems of the separation system prevalent in Latin American society from various perspectives. It separates me and the others as well as the past and the present. It makes the memory of history void and paralyzes the consciousness of history. These systems are fixed for convenient governance. In this situation, the pattern of violence becomes more explicit and broad. The anxiety and fear of the Latin American public become commonplace. It is a reality of enduring daily life without hope. Galeano finds this enduring force in historical memory. He believes that when the past and the present meet and embrace, a new history of the future can be encountered. Galeano does not just criticize reality or cynical attitude but also suggests hope for the future.