• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.3
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• pp.310-317
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• 1997

Due to the congestion of the radio spectrum, frequency bands are shared among the communication systems. Therefore for the satisfactory operation we have to predict with reasonable accuracy the levels of interference that might exist among them. Inter- ference among the communication systems depends on many factors such as climate, radio frequency, time percentage of interest, distance and path topography. Interference due to rain scattering is the most important factorin Ghz frequencies. ITU-R offers the model related to interference due to rain scattering. In this paper the transmission loss due to rain scattering is predicted and compared with the measured results.

• IE interfaces
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• v.16 no.4
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• pp.450-462
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• 2003

In this paper, we deal with a process and layout design for producing a planned amount of Sikhye in a given limited time period under a reasonable production schedule. We represent a Sikhye production line as a vector N, the element of which denotes the number of tanks required in each process and our objective is to find an appropriate vector which minimizes the total investment cost. We suggest a systematic method for finding an appropriate N and an appropriate layout to N. In detail, first, we decide the required sequence of processes and the required operations for each process and we estimate standard operating times. Second, constructing a precedence diagram, we find a critical path in order to reduce the total production lead time for a batch of Sikhye. Third, given a limited N space, we manage to construct manually each production schedule using both the processing times of the critical operations and transfer times. Finally, we find an optimal vector N which gives a minimum investment cost and meets both the time constraint and quantity constraint. In addition, with the estimated relative size of each tank, we suggest an appropriate conceptual layout design including an expansion area for future demands, based on the span technique used in the field of architectural design.

• Atmosphere
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• v.25 no.2
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• pp.193-203
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• 2015

A large aperture scintillometer (LAS) was deployed with an optical path length of 2.1 km to estimate turbulent sensible heat flux (${\mathcal{Q}}_H$) over a highly heterogeneous urban area. Scintillation measurements were conducted during cold season in November and December 2013, and the daytime data of 14 days were used in the analysis after quality control processes. The LAS-derived ${\mathcal{Q}}_H$ show reasonable temporal variation ranging $20{\sim}160W\;m^{-2}$ in unstable atmospheric conditions, and well compare with the measured net radiation. The LAS footprint analysis suggests that ${\mathcal{Q}}_H$ can be relatively high when the newly built-up urban area has high source contribution of the turbulent flux in the study area ('northwesterly winds'). Sensitivity tests show that the LAS-derived ${\mathcal{Q}}_H$ are highly sensitive to non-dimensional similarity function for temperature structure function parameter, but relatively less sensitive to surface aerodynamic parameters and meteorological variables (temperature and wind speed). A lower Bowen ratio also has a significant influence on the flux estimation. Overall uncertainty of the estimated daytime ${\mathcal{Q}}_H$ is expected within about 20% at an upper limit for the analysis data. It is also found that stable atmospheric conditions can be poorly determined when the scintillometry technique is applied over the highly heterogeneous urban area.

• Knowledge Management Research
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• v.13 no.5
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• pp.43-64
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• 2012

Emerging technologies have significant implications in establishing competitive advantages and are characterized by continuous rapid development. Efficient benchmarking is more and more important in the development of emerging technologies. Similar input level and importance are two necessary criteria need to be considered for emerging technology's benchmarking. In this study, we proposed a sequential use of self-organizing map(SOM), data envelopment analysis(DEA) and analytical hierarchy process(AHP) method for the stepwise benchmarking of emerging technology. The proposed method uses two-level SOM to cluster the emerging technologies with similar required input levels together, then, in each cluster, uses DEA-BCC model to evaluate the efficiencies of the emerging technologies and do tier analysis to form tiers. On each tier, AHP rating method is used to calculate each emerging technology's importance priority. The optimal benchmarking path of each cluster is established by connecting the emerging technologies with the highest importance priority. In order to validate the proposed method, we apply it to a case of biotechnology. The result shows the proposed method can overcome difficulties in benchmarking, select suitable benchmarking targets and make the benchmarking process more efficient and reasonable.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.6
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• pp.555-562
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• 2010

Currently digital TRS is providing the voice-oriented service based on stat-tree topology of 2.5G. As result of that, it has alimitation to accept the wide band multimedia services. Therefore, this paper designed the mesh topology based on packet networkand proposed the algorism of dynamic path establishment based on priority. In korea case, we confirmed that hop numbers priority base is more reasonable than distance priority base. And counted the trunk traffic including redundancy traffic to prevent the bottlenect situation and trouble. Also analysed the bandwidth between network management centers of backbone and access.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.3
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• pp.18-31
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• 1999

The research deals with external space Seowon(lecture hall) dedicated to education and memorial rises in Sangju area of Choson Dynasty. Characteristics of Seowon as follow; 1. Seowon of Sangju area were built from the middle of 17C to the beginning of 18C. Ideological background of building functioning were grafted into the belief in the three God governing Childbirth, the theory of feng-shui(wind-and water-magic) which is in close connection with the principles of yin and yang, and confucianism and the philosophy of lao-tze and chung-tze. The formation of space were horizontally arrangement and vertical arrangement as the first-learning and then-ancestor shrine of Youngnam provinces. 2. Background and factors of site selection were applied geographical feature, tried to connect owner home town. 3. The shape of path of flow were simple of vertical and curved composition, were continued, were stabilized through composition of human scale's space by reasonable internal. A case of Sangju area, D/H ratio of the front area of buildings and courts was as follows. D/H=1>Hyangkyo> houses on the river>temples>lecture halls. D/H ratio ot the backside areas is as follows. D/H=1>Hyangkyo>houses on the river>lecture halls. 4. Inner garden were planted deciduous than evergreen trees with Lagerstroemia indica. Enclosed dominant trees were planted by Pinus densiflora, Querces seuata.construct GEM strain, and examined for the expression and functional stability in microcosms.

• Journal of Family Resource Management and Policy Review
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• v.1 no.2
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• pp.1-15
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• 1997

The purpose of this study is to investigate (1)the level of the urban housewives’behavior and satisfaction of wedding, (2)the influential factors related to the two dependent variables above mentioned. So that provides some fundamental materials to improve the level of sound wedding culture and the whole home living. The subjects were 356 housewives, in April, 1997, Seoul. The data obtained were analyzed by Mean, Pearson’s correlation, Stepwise Multiple Regression and Path Analysis. The major findings were as follows: 1) The general tendency of the housewives’wedding behavior and satisfaction was reasonable. 2) According to the background variables(ie: marital form, the existence of job, the recognition degree of her husband’s family’s living standards, the recognition degree of her parents’home’s living standards, the perception of marital transactions), the housewives’wedding behavior was significantly different. 3) According to (1)the background variables(ie: communication frequency in household, self-acceptance, the adequacy of household income, educational level), (2)intermediated variable(ie: articles essential to a marriage), the housewives’wedding satisfaction was significantly different. 4) The indirect variable of the positive influence for housewives’satisfaction of wedding was marital form, the existence of job. the indirect variable of the negative influence for housewives’satisfaction of wedding was the recognition degree of her husband’s family’s living standards, the recognition degree of her parents’home’s living standards, the perception of marital transfactions.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.3
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• pp.53-58
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• 2006

This study deals with the method of post-processing in the automatic tool path generation for 5-axis NC machining. The 5-axis NC machining cannot only cope with the manufacturing of complicated shapes, but also offers numerous advantages such as reasonable tool employment, great reduction of set-up process and so on. Thus 5-axis NC machining has been used for aircraft parts, mold and die as well as for complicated shapes such as impeller, propeller and rotor. However, most of the present CAM systems for 5-axis NC machining have limited functions in terms of tool collision, machine limits and post-processing. Especially 5-axis machine configurations are various according to the method which the rotational axes are adapted with the table and spindle. For that reason, In many cases the optimal numerical control (NC) data cannot be obtained or considerable time is consumed. To solve this problem, we applied a general post-processor for 5-axis NC machining. The validity of this post-processor should be experimentally confirmed by successfully milling to a helix shaped workpiece.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1186-1194
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• 2012

In order to resolve the energy efficiency in wireless sensor networks, a multihop transmission technique is utilized. However, multihop transmission in wireless sensor networks (WSN) has pros and cons. It reduces total energy consumption, while it may cause a severe decrease in network lifetime. To solve this problem, we suggest the so called strike and bargaining algorithm (SBA). The routing path is determined by wages of nodes. Each node negotiates its wage with their neighbor nodes and determine a reasonable value to reach a optimally balanced point. By analysis and simulations, we show SBA can achieve a near optimal solution.

• Management Science and Financial Engineering
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• v.17 no.1
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• pp.79-94
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• 2011

Team orienteering, an extension of single-competitor orienteering, is the problem of determining multiple paths from a starting node to a finishing node for a given allowed time or distance limit fixed for each of the paths with the objective of maximizing the total collected score. Each path is through a subset of nodes, each of which has an associated score. The team orienteering problem has many applications such as home fuel delivery, college football players recruiting, service technicians scheduling, military operations, etc. Unlike existing optimal and heuristic algorithms often leading to heavy computation, this paper suggests two types of priority rule based heuristics-serial and parallel ones-that are especially suitable for practically large-sized problems. In the proposed heuristics, all nodes are listed in an order using a priority rule and then the paths are constructed according to this order. To show the performances of the heuristics, computational experiments were done on the small-to-medium sized benchmark instances and randomly generated large sized test instances, and the results show that some of the heuristics give reasonable quality solutions within very short computation time.