• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.5
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• pp.82-91
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• 2007

Currently, bridges are regarding as the structure with formative, scenic and environmental values more than their function as simple passageways. Because an attempt to work on the diversity of the bridge types and installation of the large structures on bridge are part of the project of the regional amenity enterprises, a study that harmonizes bridges with landscape is needed at this point in time. This background can influence the direction of bridge landscapes that considers local features by analysis of visual preferences on a bridge simulated scene. The results were as follows: analyzing the change of the simulated landscape image, forest landscape are damaged by the input of a bridge which was natural, harmonic and intimate. On the other hand, when a bridge was inserted into the ocean landscape, it was thought to improve the ocean landscape, especially, upper part form of arch bridge various or suspension bridge were improved in polished and various image. The insertion of a bridge into an urban landscape change from a negative image to a beautiful, harmonic and attractive image. The intimate, harmonic and natural image of a rural landscape was damaged by inserting a bridge. As analysis result about change of landscape preference by input of bridge, there is difference between before and after as input the bridge, and bridge influences as main object in the simulated scene. Visual preference was the highest in the ocean landscape, and the lowest in the suspension bridge in the rural landscape. The complicated shape of bridge follows on the background type difference certainly appear. Thee simulated scene preference except the urban landscape of the simulated scene fell generally Especially, fall of preference of girder bridge in the forest and ocean landscape, suspension bridge in the rural landscape appeared notedly.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.201-213
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• 2017

Water is removed from crude oil containing water by using oil separator. This study aims to develop a three-dimensional (3D) Eulerian computational fluid dynamics (CFD) model to predict the separation efficiency of air-water-oil separator. In the incompressible, isothermal and unsteady-state CFD model, air is defined as continuous phase, and water and oil are given as dispersed phase. The momentum equation includes the drag force, lift force and resistance force of porous media. The standard k-${\varepsilon}$ model is used for turbulence flow. The exit pressures of water and oil play an important role in determining the liquid level of the oil separator. The exit pressures were identified to be 6.3 kPa and 5.1 kPa for water and oil, respectively, to keep a liquid level of 25 cm at a normal operating condition. The time evolution of volume fractions of air, water and oil was investigated. The settling velocities of water and oil along the longitudinal separator distance were analyzed, when the oil separator reached a steady-state. The oil separation efficiency obtained from the CFD model was 99.85%, which agreed well with experimental data. The relatively simple CFD model can be used for the modification of oil separator structure and finding optimal operating conditions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.10A
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• pp.980-989
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• 2002

In this paper, we have proposed the sectorization method of the adaptive sector antenna and the new receiver structure for the CDMA wireless multi-media communication which uses multi-code and single-code. The sectorization and average BER performance of the adaptive sector antenna, which employs the proposed sectorization method, are obtained through simulation. The simulation results have shown that the sizes of sectors are properly controlled according to the distribution of the load and that the BER performance of the adaptive sector antenna is enhanced much more than that of the fixed sector antenna. Also, we have proposed two receivers, which are different from the positions to detect multi-code signals, for the multi-media communication. Each receiver has a simple cancellation scheme and two adaptive sector antennas, which are called the 1st adaptive sector antenna and the 2nd adaptive sector antenna, respectively. In this paper, the average BER performances of the receivers are compared through simulation. As the results of the simulation, we have recognized that all user' BER performances are greatly dependent on the positions to detect the multi-code signals. When we consider both system complexity and terget BERs of signals, we have concluded that the receiver, which detect multi-code signals in the 1st and the 2nd adaptive sector antenna, is appropriate for the CDMA wireless multi-media communication systems.

• Journal of the Korea Institute of Building Construction
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• v.14 no.3
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• pp.207-215
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• 2014

As a reinforcement material for RC members, the modified epoxy mortar has been reported one of the superior materials since the material can improve the load capacity and the seismic performance of the RC members. However, there were few experimental studies and analytical research for improving seismic performance with the material. This study is to propose an effective reinforcement plan for RC Ordinary Moment Resisting Frame (OMRF) with the evaluation of seismic performance and economic analysis. For the objective, first, the load-deflection curve of a simple beam specimen was compared with the analytical results. Second, a 5-story RC OMRF structure was designed only for gravity load and the alternatives for seismic reinforcement were suggested. Third, pushover analysis was executed for evaluation of design coefficients and seismic performance of the structures. Finally, an effective reinforcement plan was suggested based on the results of quantity take-off and economic analysis. The findings of this study can be utilized as the basic data when the modified epoxy mortar is applied to practice for improving the seismic performance of RC members.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.2
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• pp.167-172
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• 2004

In the human skin, vitamin C (L -ascorbic acid) that is well known as the activated materials has effects that is skin anti-aging and wrinkle repair by giving impetus to collagen biosynthesis and anti-oxidation, and that is the sun screen, a wound recovering, inhibition melanogenesis and so on. In spite of its effects, vitamin C has the defects of the skin stimulation and easily oxidized instability by water, air, heat and light. For solving their matters, many investigation is advanced and its results are synthesized the various vitamin C derivatives. And yet they have not solved the unstable property of vitamin C and were still insufficient for the comparing with the effect of the pure vitamin C itself. In this study, in order to prepare vitamin C derivative of being improved the stability and to apply vitamin C effect in the skin, we prepared new vitamin C derivative, phytosphingosine ascorbate, by using phytosphingosine, one of sphingolipids, which have a distinguished skin affinity. Phytosphingosine ascorbate can be prepared as the ionic bond between amine group (-NH$_2$) of phytosphingosine and hydroxy group (-OH) of vitamin C by way of the relatively simple reaction. So the structure and properties of the synthesized phytosphingosine ascorbate was confirmed the use of elemental analysis (C 58.3 : H 9.3 : N 2.8 : O 29.5), MALDI TOF-MS (Mw=492.58), Ultraviolet spectra (268.5nm), lH NMR, FT-IR spectra, thermal analysis (m.p=l54$^{\circ}C$), HPLC and so on. And we could confirm the anti-bacterial and anti-oxidation effects. Based on these results, we could confirm to prepare a new material that was expected of both effects of vitamin C and phytosphingosine and that is improved properties of vitamin C.

• Spatial Information Research
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• v.17 no.3
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• pp.329-339
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• 2009

A historical and cultural map needs an overall reflection of the links based on time and space among the various composite factors, instead of requiring a simple collection of the respective relics in a particular region. The study of history, culture and living environment of river system area, a place that is known to as a cradle of civilization, will be able to undertake a role in the research and comparison with other cultural regions, reaching beyond the regional units until now and moreover investigation the international and intercontinental history of civilization. In this context, this research focuses on the establishment of a cultural information system for the public use and the insight to the regional identity and materialization of culture based on Korea's peculiar history and culture. Thus, the information system for Youngsan River area aims to create a form of electronic map that contains various cultural and historical information on river system area, which is a integrated information system based on Web GIS that is open to public use through the internet. The above mentioned system is a combined product from the basic research data on various fields of study, including archaeology, architecture, arts, ecological environment, history, folk customs, literature, and food, while it aims for not only its utilization in interdisciplinary studies but also creating new value as a public database. As a result, the expected effects due to the establishment of historical and cultural information system based on Web GIS of Youngsan River area are as follows: First, the study can contribute to verify a road map of the study on Youngsan River area. Second, it will take a role to stimulate the academical research on the dynamic structure and characteristics of the Youngsan River area. Third, we can also expect an effect of gaining a full foothold in providing an electronic academic source specialized for the study of the historical and cultural map.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.5
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• pp.107-116
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• 2011

In this paper, a traffic adaptive sleep based medium access control (TAS-MAC) protocol for wireless sensor networks (WSNs) is proposed. The protocol aims for WSNs which consist of clustered sensor nodes and is based on TDMA-like schema. It is a typical schedule based mechanism which is adopted in previous protocols such as LEACH and Bit-Map Assisted MAC. The proposed MAC, however, considers unexpected long silent period in which sensor nodes have no data input and events do not happen in monitoring environment. With the simple traffic measurement, the TAS-MAC eliminates scheduling phases consuming energy in previous centralized approaches. A frame structure of the protocol includes three periods, investigation (I), transmission (T), and sleep-period (S). Through the I-period, TAS-MAC aggregates current traffic information from each end node and dynamically decide the length of sleep period to avoid energy waste in long silent period. In spite of the energy efficiency of this approach, the delay of data might increase. Thus, we propose an advanced version of TAS-MAC as well, each node in cluster sends one or more data packets to cluster head during the T-period of a frame. Through simulation, the performance in terms of energy consumption and transmission delay is evaluated. By comparing to BMA-MAC, the results indicate the proposed protocol is more energy efficient with tolerable expense in latency, especially in variable traffic situation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.42-48
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• 2008

Next generation wireless communication systems require RF transceivers that enable multiband/multimode operations. Polar transmitters are known as good candidates for high data rate systems such as EDGE (Enhanced Data Rates for GSM Evolution), WCDMA (Wideband Code Division Multiple Access), and WLAN (Wireless Local Area Network) because they can obtain high efficiency by using efficient switched-mode RF power amplifiers. In this paper, we investigate the performance of a simple peak windowing scheme for the OFDM (Orthogonal frequency Division Multiplexing) polar transmitter, which requires no change of a receiver structure or no additional information transmission. The approach we employed is to apply the peak windowing scheme to the amplitude modulated signals of the polar transmitter to reduce the PAPR (Peak-to-Average Power Ratio). The BER (Bit Error Rate) and EVM (Error Vector Magnitude) performances are measured for various window types and lengths. The simulation results demonstrate that the proposed algorithm mitigates out-of-band distortion introduced by clipping along with PAPR reduction.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.11
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• pp.187-192
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• 2014

Various researches are performed to extract significant features from continuous images. The FAST algorithm has the simple structure for arithmetic operation and it is easy to extraction the features in real time. For this reason, the FPGA based hardware accelerator is implemented and widely applied for the FAST algorithm. The hardware accelerator needs the threshold to extract the features from images. The threshold is influenced not only the number of extracted features but also the total execution time. Therefore, the way of threshold control is important to stabilize the total execution time and to extract features as much as possible. In order to control the threshold, this paper proposes the PI controller. The function and performance for the proposed PI controller are verified by using test images and the PI control logic is designed based on Xilinx Vertex IV FPGA. The proposed scheme can be implemented by adding 47 Flip Flops, 146 LUTs, and 91 Slices to the FAST hardware accelerator. This proposed approach only occupies 2.1% of Flip Flop, 4.4% of LUTs, and 4.5% of Slices and can be regarded as a small portion of hardware cost.

• Journal of architectural history
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• v.3 no.1
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• pp.101-122
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• 1994

This paper is one of the sequels from 'A Survey of Villages and Dwellings of Korean Immigrants in the North-Eastern Part of China'. It is the result of the extensive survey of Ch'ang-ts'ai-tsun village and covers several architectural characteristics of the dwellings. This paper alma to identify the 'double file' dwelling type, which is believed as one of the main stream of Korean folk dwelling. In this type, 'Chung-ju-kan' forms the central open space, where main household functions are carried out. This type originates from climatic reasons and functional reasons as well. This paper also aims to clarify how the dwelling forms are changed according to the life styles of various periods. The Korean immigrants in this village have experienced rapid changes in modern times like other Chinese. Through various political movements, the original dwelling type of this village has changed to adapt various needs and functions, which shows the simple truth : dwelling form changes according to the changes of life style and social structure. In this paper the directions of chimney through various periods are analyzed to verify the differences of the house layout methods and concepts of the time. The village had grown through 3 main periods before liberation period(1946), communization period(1946 - 1966) and contemporary period (1967 - ). It is concluded as follows: 1. The village was originated in late 19th century along the east-west street, which was a major routes of Korean Immigrants to China. In this area there was no regularity in its site plan. The direction of chimney, which was usually westward, was not determined according to the location of gate. This type was kept until liberization of this area, 1946. The plans of dwellings followed Ham-kyong-do 'double file' dwelling type, '6-kan dwelling' or '8-kan dwelling'. 2. The 'New Village' area, which was formed in the communization period, has a strict regularity in its site plan. The direction of chimney was determined as opposite direction of the gate. This method was maintained until 1976, when Mao died and new 'open' policy was held by Chinese government. In this area the 'dwelling house' plan type was not changed, but its layout and size were restricted. The general form of the dwelling in this village was shaped in this period. 3. The contemporary dwellings were built in random site location. The dwelling type was changed because of the reduction of family size and the permissin of private ownership. The number of rooms was reduced but the storage rooms and domestic animal hutches were added. But the 'Chung-ju-kan', the major chacteristics of north-eastern Korea dwelling is still kept. It becomes one large 'Chtin-ju-kan' room like 'open plan' type.