• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2008.11a
• /
• pp.159-165
• /
• 2008

For deciding the profitability and feasibility of the construction project, the schematic estimation has to not only link the design decision-making but also estimate the cost with reliability. The Object-based schematic estimation system was developed for easily linking with design-making and supports to evaluate the design alternatives in the design development stage but didn't consider the cost estimated by object supplementary and parameter work item. This research presents the Integrated Object-Parameter Schematic Estimation Model in the design development stage that can lead to more accurately estimate the cost through analyzing historical data from the high-storied office buildings. For the development of the proposed model for schematic estimation, after analyzing and classifying the work items from the Bills of Quantities(BOQs) and drawings of historical data, this research proposed the methods of estimating cost in accordance with attributes of each work item using regression analysis. In addition, a case study is performed for the effectiveness as comparing the proposed model with the previous estimating model.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.3
• /
• pp.1015-1024
• /
• 2015

This paper introduces a low cost, high efficiency, high performance three-phase unified power quality conditioner (UPQC) by using four-switch three-phase inverters (FSTPIs) and an extra capacitor in the shunt active power filter (APF) side of the UPQC. In the proposed UPQC, both shunt and series APFs are developed by using FSTPIs so that the number of switching devices is reduced from twelve to eight devices. In addition, by inserting an additional capacitor in series with the shunt APF, the DC-link voltage in the proposed UPQC can also be greatly reduced. As a result, the system cost and power loss of the proposed UPQC is significantly minimized thanks to the use of a smaller number of power switches with a lower rating voltage without degrading the compensation performance of the UPQC. Design of passive components for the proposed UPQC to achieve a good performance is presented in detail. In addition, comparisons on power loss, overall system efficiency, compensation performance between the proposed UPQC and the traditional one are also determined in this paper. Simulation and experimental studies are performed to verify the validity of the proposed topology.

• Journal of Advanced Navigation Technology
• /
• v.19 no.1
• /
• pp.53-59
• /
• 2015

We consider the problems that consist of designing time, establishment cost, delay time and reliability in designing a mesh network when given link costs and traffic requirements between nodes. Designing time, establishment cost and delay time are less, reliability is higher in designing a mesh network. One of the problems designing time is solved by mesh network topology optimization and routing (MENTOR) algorithm that Aaron Kershenbaum propose, but the others remain. In this paper we propose a new mesh network design algorithm with small computational complexity that the others are solved. The result of the proposed algorithm is better than MENTOR's in total establishment cost, delay time and reliability.

• Korean Journal of Agricultural Science
• /
• v.28 no.2
• /
• pp.132-146
• /
• 2001

Rice cultivation is not only the main resource of farm income and staple food but also the root of cultural life of Korean people. Korean government has carried out irrigation water development with heavy investment to cope with water shortage in rice fanning as a link of the five years economic development plans. In spite of the continuous accomplishment of irrigation water development, the marginal benefits-costs of irrigation water has not been studied. Owing to the government full support for the operation and maintenance of irrigation facilities, price of irrigation water as a membership fee could not be formed as the municipal and industrial water prices. Accordingly this study is aimed at identifying firstly the marginal benefits-cost of irrigation water, secondly deriving the macro-econometrics models as supply and demand functions of irrigation water and thirdly examining the marginal benefits-cost ratio. The trends of supply and demand prices of irrigation water were estimated annually. Considering the marginal benefits-cost ratio as 1.3, it was identified that additional irrigation water development projects still have an economic feasibility under the present economic situation in Korea.

• Proceedings of the KIPE Conference
• /
• 2001.10a
• /
• pp.193-197
• /
• 2001

This paper presents a novel circuit topology of the double two-switch forward type high frequency transformer linked soft-switching PWM DC-DC power converter with tapped inductor filters that can operate under a condition of the low peak voltage stress across the power semiconductor devices and lowered peak current stress through the transformer for some high power applications. This circuit topology of an interleaved two-switch forward soft-switching power converter is proposed in the order to minimize an idle circulating current due to the tapped inductor filter without of any additional active auxiliary resonant-assisted snubber circuits, such as active resonant DC link snubbers and AC link snubbers, active resonant commutation leg link snubbers. The unique advantages of this power converter are less power circuit components and power semiconductor devices, constant frequency PWM scheme, cost effective configuration and wider soft-switching PWM operation range under PWM power regulations load variations. The practical effectiveness of the proposed soft-switching converter circuit topology is tested by simulations and is proved by experimental results received from the 500W-100kHz breadboard setup.

• Proceedings of the KIPE Conference
• /
• 2001.10a
• /
• pp.668-672
• /
• 2001

The utility interactive sinewave modulated inverter for the solar photovoltaic (PV) power conversion and conditioning with a new high frequency pulse modulated link is presented for domestic residential applications. As compared with the conventional full-bridge hard switching PWM inverter with a high frequency AC link, the simplest single-ended quasi-resonant soft switching sinewave modulated inverter with a duty cycle pulse control is implemented, resulting in size and weight reduction and low-cost. This paper presents a prototype circuit of the single-ended zero voltage soft switching sinewave inverter for solar power conditioner and its operating principle. In addition, this paper proposes a control system to deliver high quality output current. Major design of each component and the power loss analysis under actual power processing is also discussed from an experimental point of view. A newly developed interactive sinewave power processor which has $92.5\%$ efficiencty at 4kW output is demonstrated. It is designed 540mm-300mm-125mm in size, and 20kg in weight.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2006.11a
• /
• pp.599-617
• /
• 2006

A network model and a Genetic Algorithm(GA) is proposed to solve the simultaneous estimation of the trip distribution and traffic assignment from traffic counts in the congested networks in a logit-based Stochastic User Equilibrium (SUE). The model is formulated as a problem of minimizing the non-linear objective functions with the linear constraints. In the model, the flow-conservation constraints of the network are utilized to restrict the solution space and to force the link flows meet the traffic counts. The objective of the model is to minimize the discrepancies between the link flows satisfying the constraints of flow-conservation, trip production from origin, trip attraction to destination and traffic counts at observed links and the link flows estimated through the traffic assignment using the path flow estimator in the legit-based SUE. In the proposed GA, a chromosome is defined as a vector representing a set of Origin-Destination Matrix (ODM), link flows and travel-cost coefficient. Each chromosome is evaluated from the corresponding discrepancy, and the population of the chromosome is evolved by the concurrent simplex crossover and random mutation. To maintain the feasibility of solutions, a bounded vector shipment is applied during the crossover and mutation.

• Journal of Korean Society of Transportation
• /
• v.22 no.4 s.75
• /
• pp.135-146
• /
• 2004

For improving the effectiveness of travel information, some rational paths are needed to provide them to users driving in real road network. To meet it, k-shortest path algorithms have been used in general. Although the k-shortest path algorithm can provide several alternative paths, it has inherent limit of heavy overlapping among derived paths, which nay lead to incorrect travel information to the users. In case of considering the network consisting of several turn prohibitions popularly adopted in real world network, it makes difficult for the traditional network optimization technique to deal with. Banned and penalized turns are not described appropriately for in the standard node/link method of network definition with intersections represented by nodes only. Such problem could be solved by expansion technique adding extra links and nodes to the network for describing turn penalties, but this method could not apply to large networks as well as dynamic case due to its overwhelming additional works. This paper proposes a link-based shortest path algorithm for the travel information in real road network where exists turn prohibitions. It enables to provide efficient alternative paths under consideration of overlaps among paths. The algorithm builds each path based on the degree of overlapping between each path and stops building new path when the degree of overlapping ratio exceeds its criterion. Because proposed algorithm builds the shortest path based on the link-end cost instead or node cost and constructs path between origin and destination by link connection, the network expansion does not require. Thus it is possible to save the time or network modification and of computer running. Some numerical examples are used for test of the model proposed in the paper.

• Journal of Korean Society of Transportation
• /
• v.21 no.2
• /
• pp.71-82
• /
• 2003

The shortest path problems(SPP) are critical issues in the military logistics such as the simulation of the War-Game. However, the existing SPP has two major drawbacks, one is its accuracy of solution and the other is for only one solution with focused on just link cost in the military transportation planning models. In addition, very few previous studies have been examined for the multi-shortest path problems without considering link capacity reflecting the military characteristics. In order to overcome these drawbacks, it is necessary to apply the multi-shortest paths algorithm reflecting un-expected military incidents. This study examines the multi-shortest paths in the real networks using Shier algorithm. The network contains both military link capacity and time-based cost. Also, the modes are defined as a platoon(group) rather than unit which is used in most of previous studies in the military logistics. To verify the algorithm applied in this study. the comparative analysis was performed with various sizes and routes of network which compares with Dijkstra algorithm. The major findings of this study are as follows ; 1) Regarding the unique characteristics of the military transportation plan, Shier algorithm, which is applied to this study, is more realistic than Dijkstra algorithm. Also, the time based concept is more applicable than the distance based model in the military logistics. 2) Based on the results from the various simulations of this study the capacity-constraint sections appeared in each scenarios. As a consequence, the alternatives are necessary such as measures for vulnerable area, improvement of vehicle(mode), and reflection of separated-marching column in the military manuals. Finally. the limits and future research directions are discussed : 1) It is very hard to compare the results found in this study. which is used in the real network and the previous studies which is used in arbitrary network. 2) In order to reflect the real military situations such as heavy tanks and heavy equipment vehicles. the other constraints such as the safety load of bridges and/or the height of tunnels should be considered for the future studies.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.1A
• /
• pp.25-33
• /
• 2003

We derive the outage probabilities for the Erlang capacity and link margin based on handoffs in the reverse link of a CDMA system of 14.4 kbps/1.9 GHz band, calculate them with the same parameters, and then with the maximum realizable Erlang capacity analyze newly the cell coverage in different areas by the COST-231 model If it decreases from 5 % to 2 % in case of $E_b/N_0$=5 dB under a soft handoff, the result shows a very reliable link with additional increment of 0.88 dB in the margin and a high quality of service within the coverage decrease of 0.12 km, 0.25 km, and 1 km in a city, suburban, and open areas respectively on the decrease of 2 Erlang in the capacity. When the $E_b/N_0$ decreases from 7 dB to 5 dB within the outage probability of 5 %, it shows the increase of 9 Erlang and of 0.2 km in a city on the same margin of 2.8 dB. Then, comparing it with a single cell, it shows the decrease of more than 10 Erlang in the capacity, but the enlargement of 0.17 km, 0.3 km, and 1 km in them on the margin decrease of 1.31 dB, also, with a hard handoff, the soft handoff gain of the increase of 10 Erlang and of 0.22 km, 0.5 km, and 2 km on the decrease of 2.16 dB.