• Spatial Information Research
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• v.21 no.2
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• pp.35-43
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• 2013

The aim of this research is to analyze the priority to functions of the U-city Service Aid Organization(USAO), which is to support invigorating U-City industry. This research analyzes the relative importance and the priority about the functional area and components of UASO based on AHP. This research also performs a sensitivity analysis. The research result shows that relative importance of functional area is like following orders: 1) distribution of U-City service-related information, 2) quality certification of U-City-related products and services, 3) R&D of U-City technology, 4) standardization of U-City, 5) U-City human resource development. The relative importance order of functional components is 1) establishment of U-City information distribution organization, 2) construction and management of U-City information distribution network, 3) supporting U-City information distribution and price policy, 4) providing U-City information list for distribution, 5) preparation and application of quality certification standard of U-City products and services, 6) research on legal system of U-City items, targets, and procedures for quality certification, 7) research, analysis, and provision of U-City information distribution situation, 8) level examination of constructed infrastructures and services in U-City, 9) U-City core technology development and localization of technology, 10) standardization of collected U-City information, service classification, distribution system. This research result can be applied directly to design functions of USAO. The result also can be used for duty management, human resource planning, or resource allocation.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.834-845
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• 2011

Massive broadcasting contents such as UHD(Ultra High Definition) TV which requires multi-channel capacity for transmission has been introduced in recent years. A transmission scheme with channel bonding has been considered for transmission of massive broadcasting contents. In HFC(Hybrid Fiber Coaxial) networks, DOCSIS 3.0(Data Over Cable Service Interface Specification 3.0) has already applied channel bonding schemes for up/downstream of data service. A method unlike DOCSIS 3.0 is required to introduce a channel bonding scheme in the broadcasting service having unidirectional transmission with a downstream. Since a massive broadcasting content requires several channels for transmission, VBR(Variable Bit Rate) transmission has been emerging for the bandwidth efficiency. In addition, research on channel allocation and resource scheduling is required to guarantee QoS(Quality of Service) for the broadcasting service based on VBR. In this paper, we propose a transmission method for mass broadcasting service in HFC network and show the UHD transmission simulator developed to evaluate the performance. In order to evaluate the performance, we define various scenarios. Using the simulator, we assess the possibility of channel bonding and VBR transmission for UHD broadcasting system to provide mass broadcasting service efficiently. The developed simulator is expected to contribute to the efficient transmission system development of mass broadcasting service.

• Korean Journal of Ecology and Environment
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• v.34 no.3 s.95
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• pp.185-191
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• 2001

The morphological variation and density of the Euglena viridis cells and environmental factors of urban waterways of Daejoncheon , Jeonjucheon, Kwangjucheon, Kumhogang, Mihocheon,and Musimcheon, Korea were studied from 25December, 1995 to 5 January, 1997 in order toelucidate possible relationships among the bio-logical and abiological factors. All E. viridis cells were same in having single star-cluster of chlo-roplast lobes and included two morphotypes based on other detailed morphology. The morphotype I cells agreed well with the typical form off. viridrs and commonly occurred in most of waters and bloomed with $5386\;cells\;{\cdot}\;mL^{-1}$ in Kwangjucheon. The density of the morphotype Ipositively correlated with ammonium (r = 0.80)and nitrite (r = 0.68), while negatively with nit-rate concentration. The morphotype II cells were characterized by having randomly scattered cytoplasmic granules beneath pellicle and unevenmargined lobes of chloroplasts. The density of the morphotype II positively correlated with nitrate (r = 0.98), while negatively correlated with ammonium and nitrite. However, the density of each morphotype was not significantly related with inorganic phosphate, temperature and pH of surface water. These results indicate that E. viridis includes two morphotypes in urban waterways in Korea, that coexist in the same period and station as a response of allocation of nitrogenous nutrients.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.4
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• pp.22-32
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• 2013

Since the percentage of vehicles equipped with Hi-pass, an electronic toll collecting device, has increased rapidly, it is very crucial to determine the optimal location of Hi-pass lanes at a toll plaza in terms of traffic control and operation. In this study, the appropriateness of existing Hi-pass lanes of a toll plaza is evaluated considering its physical geometry and traffic characteristics. A new evaluating criterion called "traffic dispersion rate" is developed in order to measure the level of traffic spreading across the toll booth lanes at a toll plaza. Logistic regression models are constructed to estimate the relationship between the traffic dispersion rate and its affecting variables. The model estimation results show that several variables including Hi-pass lane traffic volume, length of toll plaza, entering/exiting taper lengths, and locations of Hi-pass lanes. The results also suggest that traffic dispersion rate can be increased by adjusting the location of Hi-pass lanes. The study enables us to quantify traffic dispersion rate which can be used to optimize the location and operation of Hi-pass lanes at toll plazas.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.3 s.345
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• pp.39-48
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• 2006

In this paper, we analyze the spectral efficiency of multicarrier-code division multiple access (MC-CDMA) scheme. First, we derive a generalized formula for the spectral efficiency according to the number of subcarriers involved in, code division multiplexing and the number of codes used (i.e., loading factor), under a given set of channel coefficients. Also, we derive a generalized formula for spectral efficiency of various reduced-complexity systems that divide the full sets of subcarriers into several groups of subcarriers for code division multiplexing. Then, through these derivations, we establish an inter-relationship between the frequency selectivity and diversity order according to the number of multipaths. From the results, we choose the smallest code length while maximizing the diversity effect, provide an optimum subcarrier allocation strategy, and finally suggest a system structure for capacity-maximizing under the smallest code length. Through numerical analyses under simulated environments, we analyze the properties of spectral efficiency of various systems with reduced complexity and choose a major contributing factors to system design and a better system design methodology. Finally, we compare the spectral efficiency of the MC-CDMA scheme and orthogonal frequency division multiplexing (OFDM) scheme to make a relationship between both schemes.

• Journal of Digital Contents Society
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• v.19 no.8
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• pp.1585-1592
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• 2018

Due to un-balancing weight allocation on the wheelchair the existing wheelchair system are faced with the risk of flipping or falling when a wheelchair goes up to a hill. In to order to be safer during riding the wheelchair, in this paper, we proposed a real-time new solution using the integrated Gyro Sensor and Tilt Sensor for controlling the balance. Because the typical property of wheelchair is for the special user who meets the difficulty in moving on foot the maintain the balance of wheel-chair systems have become important and helpful. In our method, we calculate the seat angle using information from Tilt Sensor. However, due to the law of inertia when a wheelchair is moving there is a deviation in the output value of Tilt Sensor. Therefore, we have to optimize the value of the angle by utilizing the acceleration that is the output of the Gyro Sensor. We took the advantages by using the combination of Gyro and Tilt sensors. Moreover, we also solved the consumption issue of the whole system. Through various experimentations with usage of ZigBee sensor module, the power consumption for the balancing system is reduced significantly.

• Journal of the Korea Society of Computer and Information
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• v.19 no.12
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• pp.111-121
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• 2014

In this paper, we propose tree-based hybrid query tree architecture utilizing time slot. 4-Bit Pattern Slot Allocation(4-SL) has a 8-ary tree structure and when tag ID responses according to query of the reader, it applies a digital coding method, the Manchester code, in order to extract the location and the number of collided bits. Also, this algorithm can recognize multiple Tags by single query using 4 fixed time slots. The architecture allows the reader to identify 8 tags at the same time by responding 4 time slots utilizing the first bit($[prefix+1]^{th}$, F ${\in}$ {'0' or '1'}) and bit pattern from second ~ third bits($[prefix+2]^{th}{\sim}[prefix+3]^{th}$, $B_2{\in}$ {"00" or "11"}, $B_1{\in}$ {"01" or "10"}) in tag ID. we analyze worst case of the number of query nodes(prefix) in algorithm to extract delay time for recognizing multiple tags. The identification delay time of the proposed algorithm was based on the number of query-responses and query bits, and was calculated by each algorithm.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.3
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• pp.116-126
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• 2015

In a distributed heterogeneous computing system, the performance of a parallel application greatly depends on its task scheduling algorithm. Therefore, in order to improve the performance, it is essential to consider some factors that can have effect on the performance of the parallel application in a given environment. One of the most important factors that affects the total execution time is a critical path. In this paper, we propose the CLTS algorithm for a task scheduling. The CLTS sets the priorities of all nodes to improve overall performance by applying leveling method to improve parallelism of task execution and by reducing the delay caused by waiting for execution of critical nodes in priority phase. After that, it conditionally uses insertion based policy or duplication based policy in processor allocation phase to reduce total schedule time. To evaluate the performance of the CLTS, we compared the CLTS with the DCPD and the HCPFD in our simulation. The results of the simulations show that the CLTS is better than the HCPFD by 7.29% and the DCPD by 8.93%. with respect to the average SLR, and also better than the HCPFD by 9.21% and the DCPD by 7.66% with respect to the average speedup.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5B
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• pp.273-285
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• 2012

Current TMDL based on the 'Polluter Pays Principle' in Republic of Korea is individually operated by each local government for the designed allocated pollution load of unit watershed and unit district. However, unlike the motion of the air contaminants, the polluted contaminants in a river move from upstream to downstream, and a river can affect to districts more than two. In addition, a decision making on the construction of a sewage treatment facilities follows the concept of 'economy of scale'. These reasons support the collaboration among local governments in order to reduce the costs in improving water quality. This study suggested a method to reduce water quality management cost by redistributing reduction load considering cost-effectiveness for an entire watershed. The assessment on the suggested method is conducted in Youngsan river watershed. Without variation in total load, reduction load assigned for unit watershed and unit district is retributed in the region where pollutant source is concentrated, and then water quality and cost reduction improved from the redistribution of reduction load is analyzed. The results show that the cost saved by the suggested method is KRW 124 billion for scenario-1 and 172 billion for scenario-2 considering total cost of KRW 788 billion for the existing plan. We expect that the suggested method is a good example to reduce water quality management cost in local governments for TMDL.

• Journal of Korean Society of Forest Science
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• v.86 no.3
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• pp.352-364
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• 1997

This study examined and analyzed users' behavior to recreation forest facilities and their satisfaction to recreation forest in order to offer some basal data which would be helpful to create new recreation forest, to supply users' needs in exsiting recreation forest, and to make excellent maintenance of recreation forest. The results are as follows ; Restroom, campground and forest aromatic bath ground were the most popular facilities with the users of recreation forest. And restroom, snack stand and water cooler were the most required facilities by the users. Before using recreation forest, users' expectation to enjoy aesthetics of nature, to be released from their fatigue and to rest, was the highest one. And users were satisfied most as they expected most from recreation forest. The major variables played for users' satisfaction about facility allocation and its harmony to the forest, were how clean the facilities are, how well they are repaired and maintained, how much noise users make around them, how easy to use them, and how beautiful the surroundings are. Users' satisfaction variables about vegetation condition of recreation forest, were diversity of vegetation, the shade of trees, the reservation of the forest, and the accordance of vegetation with the surroundings. Users' satisfaction variables about facility condition in recreation forest, were how easy to access to the recreation facilities and restroom, how clean they are, how well the trash cans are allocated, how easy to access to the field kitchen. And how good the forest is protected and nurtured, how well the forest managers conduct users' behavior, how effectively recreation forest is guided and informed to the public, were their major satisfaction variables about the management of Recreation Forest.