• ETRI Journal
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• v.22 no.1
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• pp.30-37
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• 2000

Existing tree construction mechanisms are classified into source-based trees and center-based trees. The source-based trees produce a source-rooted tree with a low delay. However, for the applications with multiple senders, the management overheads for routing tables and resource reservations are too high. The center-based trees are easy to implement and manage, but a priori configuration of candidate center nodes is required, and the optimization mature such as tree cost and delay is not considered. In this paper, we propose a new multicast tree building algorithm. The proposal algorithm basically builds a non-center based shared tree. In particular, any center node is not pre-configured. In the purposed algorithm, a multicast node among current tree nodes is suitably assigned to each incoming user: Such a node is selected in a fashion that tree cost and the maximum end-to-end delay on the tree are jointly minimized. The existing and proposed algorithms are compared by experiments. In the simulation results, it is shown that the proposed algorithm approximately provides the cost saving of 30% and the delay saving of 10%, compared to the existing approaches. In conclusion, we see that the cost and delay aspects for multicast trees can be improved at the cost of additional computations.

• KIEAE Journal
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• v.16 no.4
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• pp.21-30
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• 2016

Purpose: Energy saving in the built facilities is getting important due to energy crisis. The Korea government has been implemented several energy and green building policies and practices. The both of government and industry also developed green building strategies ant technologies to reduce energy consumption and carbon emission. The purpose of this research is to identify applicable green building strategies and technologies for that can be cost effective and applicable to a multiplex house. Method: This research identified appropriate green building strategies from analysing green building strategies from G-SEED certified apartment projects and popular green building strategies. This study also adopted a survey research method to find out the applicable green building strategies for a multiplex housing. In addition, this research also conduct cost estimating to identify initial cost premium of green building strategies. Results: The research outcomes in this study guide a building owner to know about initial cost premiums of green building strategies and technologies and an architect and contractor to identify appropriate and cost effective green building strategies that can be applicable to a multiplex house.

• Korean Journal of Plant Resources
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• v.9 no.1
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• pp.63-69
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• 1996

The experiment was conducted to reduce the labor and production cost with the labor save of harvest in cultivating the onion using the machine and the results are as follows. On labor saving effect in transparent vinyl mulching, digging working hours per 10a in the case of using tractor are 55 min., fixing + turning time is 11 min.,the time of harvest is 66 min, digging working hours using cultivator are 90 min. and fixing + turning time is 9 min., but the time of hand harvesting is 693 min and 41 sec. and in digging labor saving effect, tractor shows 90% in the harvesting period and harvest by cultivator 86%. On nonmulching cases, the harvest by tractor takes 44 min. and that by cultivator does 75 min, and digging labor saving effect shows 93.6% in the tractor harvest and 89% in the cultivator harvest. Therefore, on the operation efficiency per hour, in the case of tractor with digger vinyl mulching and nonmulching show $0.091\sim0.136ha$ and in the case of cultivator with digger-both show $0.061\sim0.08ha$, but in the case of hand harvest, vinyl mulching and nonmulching are $0.008\sim0.009ha$, so in the mechanized harvest of onion, the harvest by tractor with digger is the best. On the cost and labor save for harvesting the onion with labor saving effect, tractor shows 19 hours and 26min./10a in vinyl mulching and 18 hours and 54min./10a in nonmulching, so it shows the short hours for harvesting. And labor saving effect shows 37% in comparison with 29 hours and 49 min. $\sim30$ hours and 38 min.($110,587\sim113,925won$) of the hand harvest, so the cost was reduced to $69,525\sim72,225won$. On the cultivator with diggers, vinyl mulching takes 19 hours and 49 min and nonmulching 20 hours and 2 min., so the labor saving effect and cost were reduced to $32\sim36%$($73,087\sim75,075$ won) in comparison with the hand harvest.

• Journal of Ocean Engineering and Technology
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• v.26 no.3
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• pp.1-5
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• 2012

A complex energy saving device has been developed for middle class vessels. The propulsive performance of the developed device is described through a model test. The pre-swirl stator, which recovers the rotational energy of the propeller slipstream, is a well-known energy saving device for large vessels. The pre-swirl stator for a large vessel is usually cast as a part of the stern frame and has a high cost. The manufacture of a cast stator for an existing vessel is almost impossible. The complex device that was developed can be fitted on astern frame by welding. The model tests show a 4-6% efficiency gain for middle class vessels with the developed appendages compared to those with bare hulls.

• Journal of Korean Society of Transportation
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• v.17 no.1
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• pp.41-52
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• 1999

Recently, much literature has surveyed the economic effects of transportation investment, focusing on the relationship between transportation infrastructure investment and economic development. Although the conventional views assume that transportation investment stimulates economic growth, the results of recent studies are not conclusive and in some cases reject the conventional views. The contradictory results are linked with double counting Problem and Keynesian/Neo-classical economics theory. This article investigates the economic effects of road transportation with regard to freight transport using Stated Preference technique. This study examines, in particular, the value of time saving for freight which has been rarely studied in this area. In the first part, the value of time saving, excluding the value for driver and operating cost, is theoretically investigated through the model of continuous review system and periodic review system. At last, the empirical study using the Seated Preference technique shows the value of time saving for freight and the value of reliability, compared with other studies and the value of those in COBA. The result makes us conclude that road investment produces the secondary effects as well as the direct benefit such as time saving for passengers, operating cost saving. and accident cost reduction. The secondary effect includes the contribution to economic development.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.260-265
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• 2001

This paper describes total flow control of an ice slurry system for pump energy saving. Similar turbo machinery has a characteristic that input power ratio is proportional to the three time of revolution speed ratio. To reduce the energy cost of brine pump in ice slurry storage systems, inverter is adapted instead of 3-way valve to control the speed of brine pump motor. One type of cooling load profile was used as driving load of the system, generated by a boiler and warm water storage tank. As results of the laboratory test, energy consumption and cost of the pump were reduced by 11.4%.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.475-478
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• 2004

Tool costs can comprise a significant part of the total operating costs of Flexible Manufacturing Systems. We address the problem of determining the optimal processing times of individual operations and routing mix in FMSs with multiple routes for each part type in order to minimize tool cost, subject to meeting a throughput constraint for each part type. The problem is formulated as a nonlinear program superimposed on a closed queueing network of the FMSs under consideration. Numerical examples reveal the potential of our approach for significant saving in tool costs.

• Korean Journal of Agricultural Science
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• v.22 no.2
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• pp.231-243
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• 1995

This paper aims to study regional difference in strawberry farming technology and its causal factors based on the survey of controlled strawberry farmers in three major strawberry cultivating regions, which are Nonsan county of Chungnam Province, Damyang County of Junnam Province and Guchang County of Kyungnam Province. There are differences in variety adoption, packaging and grading method which cause the farming income gap among these regions. Farmers of Guchang County, who adopt new variety Yeobong and packing system, raised highest gross receipts but ranked next to Damyang in terms of net income because of high packing cost. Farmers of Nonsan County earned lowest income because of poor quality and low price in spite of adopting packing cost saving method. Therefore, results of this study shows that successful farming technology depend on whether or not farmers adopt market oriented technology. It is suggested that direction of strawberry farming technology should focus on adopting new varieties which can contribute to increasing farmers' paid price and developing technology of reducing cost such as labor saving and packing machine.

• Quality Improvement in Health Care
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• v.14 no.1
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• pp.55-59
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• 2008

Background : The purpose of inner cannula is to protect the upper air way and permit air to pass freely, in addition, to provide endotracheal suction, artificial respiration and to maintain adequate oxygen saturation. The tube needs to be sterilized for maintenance and cleanness of air way and for prevention of bronchospasm. However, it has been reported that there is no guideline for sterilization and many hospitals conduct their own sterilization methods, for example, once a day(13's general hospital), three times a day(The Catholic University of Korea ST Mary's hospital) or even no cleansing. Consequently, the QI team of our hospital suggested the SOP(standard operating procedure) of sterilization and evaluate cost and time effect in nursing. Method : 1) Benchmarking of 13's neurosurgery department of general hospital in Seoul 2) Investigation of test records of sputum culture from patients with intubation for tracheotomy 3) Check of results of O2 Sat. monitoring to confirm of maintaining opened air way Result : 1) Improvement of process: decrease of excess sterilization of inner cannula (from 3 times a day to once a day) 2) Cost effects: saving over 10 million won per one year 3) Providing better nursing: time effects (30 min a day) permit to conduct more nursing activities Conclusion : It can get Cost and time effects in nursing with improved sterilization method of inner cannula. It needs to do research on improvement of the monthly exchange protocol of outer cannula and provide supporting data for the proper exchange schedule. The result of additional microorganism detection from patients with new process needs to be evaluated further more.

• Journal of Korea Port Economic Association
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• v.33 no.2
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• pp.97-109
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• 2017

The Terminal Operating Company (TOC) decides to replace the harbor cranes in order to increase revenue and profit through the improvement of unloading efficiency. To achieve this goal, substantial costs and efforts are necessary. However, the conative participation of harbor stakeholders is needed, because they will certainly be passionate enough when expected effects are obvious. The purpose of this study is to analyze the effect on stakeholders on direct and indirect cost saving when the cargo handling equipment is replaced. According to the analysis, a total cost saving of 6,561.8 million won will arise including a vessel chartering fee of 3,649.6 million won, a port facility fee of 1,528.8 million won, and fuel costs of 1,383.4 million won as direct effects. As indirect cost effects, a total cost saving of 3,107.0 million won will emerge including an environmental pollution cost of 2,134.8 million won and a freight inventory cost of 972.2 million won. Consequently, the replacement of harbor cranes in the TOC has positive effects on shipping companies, shippers, and the government in terms of costs and other aspects. The results of this study can be utilized as a basis to draw a conative cooperation of stakeholders on TOC's promotion of the harbor cranes replacement.