• Journal of Korean Society of Water and Wastewater
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• v.18 no.1
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• pp.49-58
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• 2004

This study is to analyze the affecting factors to the peak factor in the drinking water supply Facilities. The peak factor is a very important element to determine the capacity of the water supply facllities. Several factors such as Population served, average day water demand, ratio of domestic water use, ratio of affairs & business water use and water use per capital per day were selected as the affecting factors in this study. In this study, peak factor characteristics for Korean facilities were compared with those for Japanese ones. As a result, non-exceedance probability was suggested as the designing method for the peak factor. Also, the 50% non-exceedance probability values and the 90% values based on the 1998-1999 data were suggested in this study.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1198-1206
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• 2010

Recently smart phone and tablet PC are regarded as the most valuable mobile devices, so the demand of customers for multimedia supporting has been greatly increased. The network operators are now considering the deployment of relay stations ensuring low installation costs for its service cell to improve the cell capacity. Enhancing the relay stations, however, increases intra-cell interference, which is affecting the quality of service and outage ratio. In this paper, we present MPFR(Multihop Partial Frequency reuse) as the new frequency reuse scheme to increase cell throughput while maintaining low outage ratio for the OFDMA cellular multihop networks. Dynamic power control is also introduced to improve cell capacity. Overall cell throughput and outage ratio are observed by the simulation, and comparison between MPFR and conventional multihop frequency reuse schemes is convincing the performance enhancement.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.6
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• pp.2398-2421
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• 2020

In third world countries like Pakistan, the production of electricity has been quickly reduced in past years due to rely on the fossil fuel. According to a survey conducted in 2017, the overall electrical energy capacity was 22,797MW, since the electrical grids have gone too old, therefore the efficiency of grids, goes down to nearly 17000MW. Significant addition of fossil fuel, hydro and nuclear is 64.2%, 29% and 5.8% respectively in the total electricity production in Pakistan. In 2018, the demand crossed 20,223MW, compared to peak generation of 15,400 to 15,700MW as by the Ministry of Water and Power. Country faces a deficit of almost 4000MW to 5000MW for the duration of 2019 hot summer term. Focus on one aspect considering Demand Side Management (DSM) cannot oversea the reduction of gap between power demand and customer supply, which eventually leads to the issue of load shedding. Hence, a scheduling scheme is proposed in this paper called RPSMDSM that is based on selection of those appliances that need to be only Turned-On, on priority during peak hours consuming minimum energy. The Home Energy Management (HEM) system is integrated between consumer and utility and bidirectional flow is presented in the scheme. During peak hours of electricity, the RPSMDSM is capable to persuade less power consumption and accomplish productivity in load management. Simulations show that RPSMDSM scheme helps in scheduling the electricity loads from peak price to off-peak price hours. As a result, minimization in electricity cost as well as (Peak-to-Average Ratio) PAR are accomplished with sensible waiting time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1903-1911
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• 2016

As interest in MANET is increasing nowadays, research upon an efficient MANET routing protocol is actively under way. A LQA(Link Qualty Aware)-AODV routing protocol to deal with frequent changes of topology and wireless link variations under tactical operating conditions is proposed in this paper. The suggested LQA-AODV takes into account the channel capacity of each hop during the route request process of the traditional AODV protocol. In detail, LQA-AODV adds a channel capacity cost value to the RREQ message format that occurs during the routing process of the existing AODV Routing Protocol causing the accumulated channel capacity cost values of each sections to be compared before establishing a route. To verify the performance of LQA-AODV, NS2.35 was utilized and the Link-Quality Model was applied in order to reflect the tactical wireless environment. The simulation compares and analyzes LQA-AODV and the existing AODV, showing a large improvement over the traditional AODV in regards to the Packet Delivery Ratio, and End-to-End Delay.

• Journal of the Earthquake Engineering Society of Korea
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• v.26 no.3
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• pp.105-116
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• 2022

Seismic demand on nonstructural components (NSCs) is highly dependent on the coupled behavior of a combined supporting structure-NSC system. Because of the inherent complexities of the problem, many of the affecting factors are inevitably neglected or simplified based on engineering judgments in current seismic design codes. However, a systematic analysis of the key affecting factors should establish reasonable seismic design provisions for NSCs. In this study, an idealized 2-DOF model simulating the coupled structure-NSC system was constructed to analyze the parameters that affect the response of NSCs comprehensively. The analyses were conducted to evaluate the effects of structure-NSC mass ratio, structure, and NSC nonlinearities on the peak component acceleration. Also, the appropriateness of component ductility factor (R_p) given by current codes was discussed based on the required ductility capacity of NSCs. It was observed that the responses of NSCs on the coupled system were significantly affected by the mass ratio, resulting in lower accelerations than the floor spectrum-based response, which neglected the interaction effects. Also, the component amplification factor (a_p) in current provisions tended to underestimate the dynamic amplification of NSCs with a mass ratio of less than 15%. The nonlinearity of NSCs decreased the component responses. In some cases, the code-specified R_p caused nonlinear deformation far beyond the ductility capacity of NSCs, and a practically unacceptable level of ductility was required for short-period NSCs to achieve the assigned amount of response reduction.

• Journal of Korea Port Economic Association
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• v.31 no.3
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• pp.107-120
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• 2015

International logistics systems for cross-border trading aim not only to reduce costs and time, but also to maximize added value. For accuracy of shipping time, cost reduction, rapidity, and safety improvement, demand for Ro-Ro shipping as a global supply chain operating system has increased. To anticipate these demands, this study estimates the optimal demand and scale of Ro-Ro berth construction by analyzing shipping volumes between Korea and Japan. Based on Ro-Ro shipping speeds and distances between Korea and Japan, the shipping volume (container and general cargo) of Busan port is sorted into two separate zones. After analyzing the ratio of items that have great potential benefits from using Ro-Ro shipping, we estimate possible shipping volumes using Ro-Ro berth provision. The results reveal that two berths for 20,000t vessels are additionally required to accommodate the estimated volume. Results suggest the construction of an exclusive Ro-Ro berth in Busan port. This would not only accommodate the demand between Korea and Japan, but also provide a way to avoid the lean-to-one-side port policy.

• Journal of Korean Society of Water and Wastewater
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• v.9 no.2
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• pp.118-126
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• 1995

The variation of the urban water demand and the amount of water in the distribution reservoir was studied with time for a day. The city of Kwangju in Korea was selected as a study area. The population of Kwangju in the end of 1993 was more than one million and two hundred thousand peoples. The average of daily water use in 1993 was about three hundred and fifty thousand tons a day. One day was devided into 12 divisions with a 2 hour increment. The water use demand related to the amount of water in the distribution reservoir was observed for the given time interval of a day. The water use index was defind in percentage that indicates the ratio of the amount of water use for a time interval to the amount of water use for a day. The water use index with consideration of the water stored in the reservoir was found to be useful to manage and to operate the water supply systems in real time.

• Journal of Korean Society of Transportation
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• v.29 no.1
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• pp.17-27
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• 2011

This paper investigates some critical errors influencing travel demand estimation in Korea Transportation Data Base (KTDB), and through this investigation reasonable traffic analysis zone (TAZ) size and internal trips ratio are analyzed. With varying zone size, the accuracy of travel demand estimation is studied and appropriate level of zone size in KTDB is also presented. For this purpose zonal structure consisting of location of zone centroid, number of centroid connecters has been constructed by social economic index, and then some descriptive statistical analyses such as F-test, coefficient of correlation are performed. From the results, this paper shows that the optimum levels of zone system were various according to the order and capacity of roads, and also shows that the smaller TAZ, the less error in this research. In conclusion, in order to improve accuracy of traffic demand estimation it is necessary to make zone size smaller.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.11a
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• pp.221-227
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• 2000

The optimal capacity of CGS(Co-Generation Sys.) for APT. complex is 300kW output of electricity power from being considered the simple payback period, loss and benefit, and the running mode of CGS. The proper operation mode of CGS is as follows; If the demanding electricity load of APT. complex is within the range of capacity of generator(300kW), CGS is connected and operated with KEPCO grid. When the load ratio is over 50% of normal load of CGS(300kW), only CGS supply electricity demand. If not, the electricity line of CGS is exchanged to that of KEPCO.

• Structural Engineering and Mechanics
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• v.51 no.1
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• pp.131-140
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• 2014

This study focuses on seismic behaviour of tall piers characterized by high slender ratio. Two analysis models were developed based on elastic-plastic hinged beam element and elastic-plastic fiber beam element, respectively. The effect of the division density of elastic-plastic hinged beam element on seismic demand was discussed firstly to seek a rational analysis model for tall piers. Then structural seismic behaviour such as the formation of plastic hinges, the development of plastic zone, and the displacement at the top of the tall piers were investigated through incremental dynamic analysis. It showed that the seismic behaviour of a tall pier was quite different from that of a lower pier due to higher modes contributions. In a tall pier, an additional plastic zone may occur at the middle height of the pier with the increase of seismic excitation. Moreover, the maximum curvature reaction at the bottom section and maximum lateral displacement at the top turned out to be seriously out of phase for a tall pier due to the higher modes effect, and thus pushover analysis can not appropriately predict the local displacement capacity.