• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.2
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• pp.339-348
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• 1990

Techniques which are able to predict and control dynamic characteristics, not affecting the vibrational characteristics on the modification of structural design, are being studied. As one of these techniques, experimental modal analysis is widely applied by many researchers. In this study, modal analysis is performed using transfer matrix method by a macro computer. The developed program would estimate the structural modal parameters precisely, and the validity of this program is certified by comparing with the experimental results of .GAMMA A. structure. Estimated modal parameters(natural frequency, vibrational mode, equivalent mass, etc.) are in accord with the experimental results. Also, the optimal location of the additive mass is determined by the evaluation of the vibrational mode and the equivalent mass. The relation between the additive mass and the equivalent mass is specified, and we come to know that the ratio of equivalent mass to additive mass alter linearly within the range of 20%.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.101-106
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• 2012

The press bulging process is very useful and productive method to produce round-type mechanical components which have not been able to be manufactured because of limitation of the conventional press technology. The application of the press bulging process has expanded very quickly in the hydraulic and electronic industry and more recently it has been used to produce other mechanical parts such as the automobile and shipping parts. This expanding application also has brought some unsolved problems and leads many researchers to put their effort into the die design of the press bulging process. In this study, to obtain the optimum die shape for the press bulging process, various process parameters have been considered such as corner radius, bulging height, pressing length, and forming load, etc. The main interest of this paper is to verify the press bulging process which has more than 4.0 in height-length ratio. From this aspect, Finite Element analysis shows great ability to simulate the precise deformation process and gives us manufacturing database. Consideration of strain, stress, and strain-rate for the various cases has been also taken to keep the forming load within a particular range.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.6169-6187
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• 2017

With the fast growth of mobile services, Mobile Cloud Computing(MCC) has gained a great deal of attention from researchers in the academic and industrial field. User authentication and privacy are significant issues in MCC environment. Recently, Tsai and Lo proposed a privacy-aware authentication scheme for distributed MCC services, which claimed to support mutual authentication and user anonymity. However, Irshad et.al. pointed out this scheme cannot achieve desired security goals and improved it. Unfortunately, this paper shall show that security features of Irshad et.al.'s scheme are achieved at the price of multiple time-consuming operations, such as three bilinear pairing operations, one map-to-point hash function operation, etc. Besides, it still suffers from two minor design flaws, including incapability of achieving three-factor security and no user revocation and re-registration. To address these issues, an enhanced and provably secure authentication scheme for distributed MCC services will be designed in this work. The proposed scheme can meet all desirable security requirements and is able to resist against various kinds of attacks. Moreover, compared with previously proposed schemes, the proposed scheme provides more security features while achieving lower computation and communication costs.

• Journal of the Korean Solar Energy Society
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• v.34 no.4
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• pp.67-74
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• 2014

The fluctuation of the output power of wind farms will be able to cause the impact on the Jeju power system such as power quality and stability. To settle the matter, many researchers have proposed the use of the BESS(Battery Energy Storage System) in the wind farm. In this paper, The BESS is applied to each wind farms for mitigating the fluctuation of wind power output. The BESS is controlled for smoothing the output of wind farms. Two kinds of simulation will be carried out. First, the simulation results by using PSCAD/EMTDC simulation program are compared to the measured data from the real power grid in Jeju Island. The other is to analyze the output of wind farms when the BESS is applied to the simulation works. The simulation results will demonstrate the effectiveness of using BESS to stabilize for power grid in Jeju Island.

• Journal of the Korea Furniture Society
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• v.25 no.2
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• pp.129-138
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• 2014

Beauty of the proportion of the furniture of the Joseon Dynasty, have been studied by many researchers along with the ideological background. Furniture Joseon, can know that it has emphasized the beauty by placing the base with simplicity and to base the natural view. However, efforts are missing try to find a logical answer about what is configured by any principle view of nature we are talking about. Therefore, in the present study, we study the beauty of proportion to the center of the hall furniture Korea dynasty, and it was studied perspective of view of nature of the times. Around the neck of the Joseon Dynasty furniture, it is going to become an opportunity to say fundamentally the culture of their own ingenious with uniqueness by reviewing the discrimination of the cultural identity. That illuminates the housing culture through the characteristics of furniture and space, to pursue the unity is going to be able to find a lot of information from a wider point of view. In this paper we present a visual furniture material for efficient survey through use of research results, it is expected that it is used as related documents that can be usefully employed in the development process of the furniture design.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.53-58
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• 2003

Many researchers have rigorously studied the nonlinear behavior of stress-strain relationship of concrete using mathematical curves. Most of model equations for stress-strain relationship, however, have been focused on old age concrete, and were not able to adequately represent the behavior of concrete at an early age. A wide understanding on the behavior of concrete from early age to old age is very important in evaluating the durability and service life of concrete structures. In previous study by authors of this paper, a stress-strain model equation for low- and medium-strength concretes was suggested. In this paper, to extend the application region of compressive stress-strain curve to high-strength concrete, an analytical research was performed. An analytical expression of stress-strain curve with strength and age was developed using regression analyses on the experimental results. For the verification of the proposed model equation, it was compared to the experimental data. The result showed that the proposed model equation was not only compatible with the experimental data quite satisfactorily but also describing well the effect of strength and age on stress-strain curve.

• Journal of architectural history
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• v.6 no.3 s.13
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• pp.61-76
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• 1997

A study on the traditional houses of North Korea(I) have been published in 1996. This paper is written to supplement the preceding paper. This paper aims at collecting new data of traditional house in North Korea. But still being prohibited for the researchers of South Korea to approach to the field, I had to depend on the memories and experiences of the immigrants from North Korea who are now living in Kangwon and Incheon Province. Through the questionnaire and drawings, they described vivid memory of their old houses. I was able to add new data of 70 cases, which are significant and valuable as much as those of the real field are. Those data, including the exisiting data, are enough for me to analize statstically the regional charateristics, the differnces among economical classes, and the periodical change. It opens the way for verfying the existing theory. Regional charateristics of house in North Korea can be described as followings: a. Hamkyong-do ; Concentrating spaces into one building, Double-fold type plan, Including 'cheongju-kan' space, Weak fences b. Pyongan-do ; Concentrating spaces into two buildings, 二 shape buildings , Single-fold type plan, Strong fence c. Pyongannam-do to Myolak mountains; Concentraing spaces into two buildings, ㄱ, ㄷ shape buildings, Single-fold type plan, Strong fence d. Southern area of Myolak mountains; Concentrating spaces into one building ㅁ shape building, Single-fold type plan with wooden floor space

• The Journal of the Korean dental association
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• v.55 no.12
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• pp.828-840
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• 2017

In recent years, many researchers and clinicians found interest in regenerative medicine using induced pluripotent stem cells (iPSCs) with biomaterials due to their pluripotency, which is able to differentiate into any type of cells without human embryo, which of use is ethically controversial. However, there are limitations to make iPSCs from adult somatic cells due to their low stemness and donor site morbidity. Recently, to overcome above drawbacks, dental tissue-derived iPSCs have been highlighted as a type of alternative sources for their high stemness, easy gathering, and their complex (ectomesenchymal) origin, which easily differentiate them to various cell types for nerve, vessel, and other dental tissue regeneration. In other part, utilizing biomaterials for regenerative medicine using cell is recently highlighted because they can modulate cell adhesion, proliferation and (de)differentiation. Therefore, this paper will convey the overview of advantages and drawbacks of dental tissue-derived iPSCs and their future application with biomaterials.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.14
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• pp.5607-5611
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• 2015

Thousands of people die each year from cancer due to occupational causes. To reduce cancer in workers, preventive strategies should be used in the high-risk workplace. The effective prevention of occupational cancer requires knowledge of carcinogen agents. Like other areas of healthcare industry, occupational health has been affected by information technology solutions to improve prevention, early detection, treatment and finally the efficiency and cost effectiveness of the healthcare system. Information technology solutions are thus an important issue in the healthcare field. Information about occupational cancer in information systems is important for policy makers, managers, physicians, patients and researchers; because examples that include high quality data about occupational cancer patients and occupational cancer causes are able to determine the worker groups which require special attention. As a result exposed workers who are vulnerable can undergo screening and be considered for preventive interventions.

• The Research Journal of the Costume Culture
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• v.9 no.6
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• pp.830-841
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• 2001

The purpose of my study is to provide some information on clothing for the handicapped with special needs. So I have designed clothes for the handicapped to provide some solutions for their clothing problems. These clothing designs for crutch and wheelchair users were based on solutions proposed by many researchers. The number of handicapped has been increasing gradually for years, especially the physically handicapped. Although they make use of many instruments for ease of movements and other physical conditions, most of the handicapped generally use crutches and wheelchairs. So I designed clothing for the crutch and wheelchair users. In order to ease problems in dressing and undressing, when using the crutch and wheelchair, various physical attributes of clothing should be considered: (1) Selection of fabric, (2) construction and location of the opening, (3) type and location of fastenings, and (4) design of garments for comfort and ease of movement. Clothing should also be able to satisfy psychological needs related to attractive appearance. My designs have proposed seven items of clothing. These include a cape-coat, over-blouse, one-piece dress and an pants for the crutch users. Also, a shirts, pants, and wheelchair wrap for wheelchair users will be displayed.