• The Journal of Society for e-Business Studies
• /
• v.21 no.4
• /
• pp.15-28
• /
• 2016

As the industry of Mobile Internet has been gradually developed, the major device for accessing the web is predicted to shift from PC to Mobile devices in the near future. This drastic increase of demand in Mobile devices has drawn a more convenient standard of living by transcending time and space in our lives, however, it triggered various side effects such as a digital divide. This study was conducted to analyze how people utilize the contents via Mobile devices and their active attitude toward Mobile Internet by dividing individual characteristics into generations, education level and income level, and also identify whether Mobile contents utilization has an effect on the active attitude. The research results could be used for establishing a policy to narrow the gap in Mobile contents use and active attitude by individual characteristics.

• Journal of the Korean Solar Energy Society
• /
• v.29 no.6
• /
• pp.102-109
• /
• 2009

The research on meteorological data in Korea has been carried out but without much consistency and has been limited to some areas only. Of relatively more importance has been the area in the utilization of the solar energy, however, the measurement of the global solar horizontal irradiation has been quite limited. In the current study, the actually measured value of the global solar horizontal irradiation from the meteorological data and the theoretically calculated value of the global solar horizontal irradiation from the cloud amount will be analyzed comparatively. The method of analysis will employ the standard meteorological data drafted by the Korean Solar Energy Society, the standard meteorological data from the presently used simulation program and the corresponding results have been compared with the calculated value of the global solar horizontal irradiation from the cloud amount. The results of comparing the values obtained from MBE(Mean Bias Error), RMSE(Root Mean Squares for Error), t-Statistic methods and those from each of the standard meteorological data show that the actually measured value of the meteorological data which have been converted into standard meteorological data with the help of the ISO TRY method give the monthly average value of the global solar horizontal irradiation. These values compared with the monthly average value from the IWEC from the Department of Energy of the USA show that the value of the global solar horizontal irradiation in the USA is quite similar. In the case of the values obtained from calculation from the cloud amount, the weather data provided by TRNSYS, except only slight difference, which means that the actually measured values of the global solar horizontal irradiation are significant. This goes to show that in the case of Korea, the value of the global solar horizontal irradiation provided by the Korea Meteorological Administration is will be deemed correct.

• Journal of Environmental Impact Assessment
• /
• v.8 no.3
• /
• pp.35-47
• /
• 1999

The purpose of this study is to research the environmental amenity factors of a city to devise the strategies to preserve the factors. For this study, the area of Masan city in Korea was chosen, and questionnaires, field studies, and statistical researches were used. Based on the results, the research showed the city surveyed had expanded by 1,069%, and the population of the city had increased by 272% from 1970 to 1995. In the city-life environment, the traffic was not smooth and the streets were not safe. The number of cars increased by 40,797% from 1970 to 1995, but the total length of roads increased only by 333%. The number of traffic accidents increased by 850%. Buildings were not preserved or maintained and did not have any traditional value. Additionally, buildings were not harmonious with environmental surroundings. Land allocation for utilization was not mixed well with tradition. In relation with the surroundings, there were not enough spaces for old people, and parking spaces were limited. In the field of public policy and finance, economic support and fundamental facilities were not enough. The survey of the household environment and the neighborhood environment showed that the room temperature, sunshine, air condition, and space were medial in the household environment. Public social facilities and entertainment culture had the lowest quality in the neighborhood environment. The city-life environment, the neighborhood environment, and the household environment affected the quality of life in order. The above results showed that cities should be planned upon sustainable development with the idea of emphasizing ecological harmony and considering people first, that citizen should be planned upon sustainable life by the harmony between people and the environment. Cities should be places where all people can live together pleasantly and cooperate with each other.

• Tunnel and Underground Space
• /
• v.22 no.5
• /
• pp.297-309
• /
• 2012

The stability assessment of abandoned gangway for the purpose of services was performed. Among the many factors that affect the stability of openings, the span of the opening in a given rock mass condition provides an important element of design. In this paper, the stability of gangway was assessed by the critical span curves proposed by Lang, the modified Mathews'stability graph method and using support measures of the Q system. In the evaluation of stability as a whole the gangway is considered as stable. But the rockfalls of wedge-shaped blocks were expected in the area in which the horizontal joints of low angle appear. The support measures such as local rock bolts are required to use for commercial purposes of the abandoned gangway. And entrance section may require the particular attention as unstable section. Since there are so many spalling due to bad blasting in the roof and sidewall of gangway, the scaling operations should be followed primarily.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.9 no.6
• /
• pp.113-119
• /
• 2010

Wireless ad hoc network composed of low power devices has been operated in ISM bands. However, with the growing proliferation of wireless services, these bands are increasingly getting congested. In order to relieve the spectrum scarcity and inefficient spectrum utilization, ad ho cognitive radio was proposed. In this paper we propose the efficient spectrum sensing method to reduce power consumption and detect white space in ad hoc cognitive radio system. The wireless channel between a licensed user and CR systems is modeled as Gaussian channel, the distance between a licensed user and CR systems is assumed differently. Also, the wireless channel among CR systems is assumed as the perfect channel and the distance among CR systems is assumed close distance. CR systems sense the spectrum of the licensed user by using a energy detection method. From the simulation results, spectrum sensing performance of combining sensing result of CR systems with high received energy shows higher than combining sensing result of all CR systems and we can refer to the proposed sensing method in order to perform effective spectrum sensing with low power consumption.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.11
• /
• pp.966-977
• /
• 2015

This paper presents a novel modified coaxial cavity resonator and its application to bandpass filters with compact size and improved quality factor(Q-factor). The proposed resonator is made up of ${\Gamma}-shape$ or curved four inner conductive posts within a single cavity, which provides quadruplet to realize bandpass filter. No metallic walls inside the cavity are required, and thus the utilization efficiency of the cavity space is improved. As a result, the unloaded Q can be approximately 15 % higher in comparison to the conventional coaxial resonator, or more than 35 % volume saving can be achieved while maintaining the similar Q-factor value with the conventional designs. In addition, due to the multiple cross-coupling occurring within the cavity, including the source-to-load coupling, four flexible transmission zeros can be created to realize different filtering functions. Simulations as well as experimental results of four- and eight-pole filters are presented to validate this attractive design concept. Good agreement between measured and computed results is obtained.

• Journal of the Korean housing association
• /
• v.26 no.5
• /
• pp.123-131
• /
• 2015

The purpose of this study is to suggest an optimum guide line of the unit plan design in national housing (less than $85m^2$ of exclusive floor area in a dwelling unit). The unit plan of apartment have been improved diversely for the residents, and the family members per household have been decreased for decades comparing with the past. In contrast, the living space per household has been increased steadily, it is because of the improvement of the living standard. The unit plan have been improved from 2-bay corridor access type and 2~3 and 4-bay staircase type. In december 2005, the balcony was permitted to be used as exclusive living area without the increase of the original living area by law. So the apartment residents have been able to use more spacious area exclusively in a dwelling unit. On the other hand, the legalization on permitting balcony area into a exclusive area resulted in a distorted wide and enlarged plan only for the business profit improvement lately. The living environment has been changed differently unlike at the time of the legislation of the national housing. The family member per household has been decreased and the related law and the institution has also been changed. Moreover It has passed 40 years since the legislation of national housing ($85m^2$). So, The size of national housing should be reviewed according to the current trend in terms of the decrease of household and the utilization of balcony area.

• Journal of the Korean housing association
• /
• v.24 no.5
• /
• pp.9-16
• /
• 2013

The purpose of this study is to analyze local-based social welfare facilities to respond to secular change of the UR rental housing estates in Japan. The selected case studies for the analysis are Hibarigaoka, Hamakousien, Turumai UR rental housing estates constructed around 1960's. The analysis was done through UR website, MLIT (Ministry of Land, Infrastructure, Transport and Tourism) and MHLW (Ministry of Health, Labour and Welfare) policy report, and related literature. These case studies are connected with housing policy as well as welfare policy and performed to Stable Living Creation Project by Business Entry System for Stable Living. The types of local-based social welfare facilities are classified by welfare corporation and medical corporation. The results are as follows: 1) The implementation of cooperative and participative system not only the private sector (welfare and medical Corporation, etc.) but also the public (MLIT, MHLW, UR Renaissance Agency, Local government, etc.). 2) Repurposed of land through rent and transfer of land for local-based social welfare facilities in the process of housing stock renewal utilization. 3) The pursue of regional revitalization through attached to multi-generation facility or local community space for elderly in local-based social welfare facilities.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.2 no.1
• /
• pp.1-7
• /
• 2006

This paper was studied for optimum design of the used vaporizer at a satellite station. Generally, the cold air is created by temperature drop on the vaporizer surface. In addition, the frost creates ice deposit layer, therefore, heat transfer on vaporizer decreases into the adiabatic condition. By this reason, recent vaporizer system is installed as parallel type, and it takes three times of vaporizer capacity. But this vaporizer system requires much installation costs and restricted by some space. It is very important to solve this problem. This study paper is regarding $LN_2$ vaporizer where the utilization increases recently. There are three variable conditions which are used in this study research. First, fin lengths of 4000mm, 6000mm, 8000mm and 0, 4, 8 fin types were applied rut each vaporizer. Second, we applied four season condition which consist of humidity, temperature and air velocity to the experimental environment. Finally, pressure was applied to get flow rate during experiment. This paper objective is to propose vaporizer type and length data for best performance of vaporizer through experiment.

• Journal of Korean Society for Geospatial Information Science
• /
• v.15 no.4
• /
• pp.3-9
• /
• 2007

Recently, the efforts of systematic understanding and utilization of geographic phenomenon for human life as a important factor among activity of mankind are increasing. It is necessary to express topography connected with space. Especially, the technology of geographic analysis using DEM can supply the information rapidly and accurately about elevation and terrain slope of the subject area under the necessity of high 3D quality geographic information. In this study, creating more precise DEM derived from LiDAR data, quantitative analysis on the subject area about elevation and terrain slope is done under comparison with Digital Topographic map Scale 1:1000. LiDAR data is more detailed than Digital Topographic map to express the elevation of the subject area ($39.89{\sim}77.48m$), and terrain slope by analysis using DEM derived from LiDAR data come out minutely about 90%. It can be concluded that the LiDAR data is very applicable and accurate for 3D topographic terrain slope analysis.