• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.6
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• pp.599-612
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• 2013

This study aims to investigate an economical efficiency of two excavation methods with respect to the room-and-pillar method for the underground space and conventional excavation method, i.e. 2-arch tunnelling method. For feasibility study, an excavation cost for both room-and-pillar method and 2-arch tunnelling method was estimated when the same space in operation was required. It was assumed that properties of reinforcements and rock were adopted from literatures. However, an excavation shape of the room-and-pillar method was assumed not to be the rectangular shape which is a general type in the room-and-pillar method but to be an arch shape in order to compare with the conventional excavation method (2-arch tunnelling) and to achieve the maximum bearing capacity of the structure during excavation. Consequently, the wider space in use or required and the better condition of rock we assumed, the more economical advantage we have in the room-and-pillar method than the 2-arch tunnelling method.

• Journal of Korean Society of Forest Science
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• v.87 no.2
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• pp.286-299
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• 1998

This study was conducted to do a comparative analysis of hunting system in 16 OECD(Organization for Economic Co-operation and Development) countries. Hunting is one of the most advanced types for developing natural resources, esp. wildlife, which is one of major products from forest. There are two types of hunting system ; Revier and/or License System, around most countries which have traditional advanced hunting and higher hunter population. Licence system, which is chosen in Korea, is less efficient ways of hunting for maximizing economical value and wildlife management than Revier system does. Adopting better system for much more efficient economical condition from hunting in Korea in a future is a ultimate goal in this study. The first step for the goal is an analysis of these two system among 16 OECD countries ; United State, Japan, Germany, France, etc. Comparative researches in hunting regulations such as number of hunters, hunter ratio to population, hunting bags, game species, seasons, ammunition and hunting permit are a next step for adopting developed hunting system in Korea. Korea has a smallest hunter ratio to population (1/2,463) among 16 OECD centuries and economical value lead by hunting is estimated still very low. Revier system is a popular one in most OECD countries except United State, Japan, etc, which is useful for wildlife management and maximizing economical value of hunting. And usually rifles are permitted for big game hunting. Hunting examination and/or insurance are compulsory for achieving hunting permit. Depend on game species, yearly hunting bag and season are constructed in most OECD countries.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.57-63
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• 2003

Aluminum Stranded Conductors Steel Reinforced (ACSR) in overhead transmission lines have slowly degraded due to pollutants in the air for a long period of time, so in the 2000, a number of them has been exceeded over their forecasted useful life. Since most of them are faced with assessment their present conditions in regard to economical maintenance, in this paper, we have suggested a method in order to evaluate the current condition of aged conductors by using dominant parameters such as elapsed years, environment index, and conductor configuration. A diagnostic system for predicting the deterioration grades corresponding to the lifetime of aged conductors is described, which is designed as an Adaptive Neuro-fuzzy Inference System (ANFIS) based on knowledge and experiences of experts. Applying this diagnostic system to practical transmission lines in domestic, it is shown that the system can be effectively used as a guide to perform nondestructive diagnosis and economical operation for old ACSR conductors.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.6
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• pp.600-606
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• 2012

Upon investigation of the damaged wheels for high speed train it was determined that the damage was caused by rolling contact fatigue during operation of train. The major problems that railway vehicle system using wheel-rail has to face during operation of railway vehicle are rolling contact fatigue, cracks in wheels, cracks in rails and wheel-rail profile wear. If these deficiencies are not controlled at early stages the huge economical problems due to unexpected maintenance cost in railway vehicle can be happened. Also, If the accurate knowledge of contact conditions between wheel and rail can be evaluated, the damage of wheel can be prevented and the maintenance operation can save money. This paper presents the applicability of electro-magnetic technique to the detection and sizing of defects in wheel. Under the condition of continuous rolling contact fatigue the damage of wheel has continuously monitored using the applied sensor. It was shown that the usefulness of the applied sensor was verified by twin disc test and the measured damaged sizes showed good agreement with the damaged sizes estimated by electro-magnetic technique.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.4
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• pp.359-365
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• 2014

Successful results of treatments using double crown prostheses for the partially edentulous patients who have a few remaining teeth have been reported in several journals. A double crown removable partial denture can be an alternative treatment for the patients with a poor periodontal condition of remaining teeth. Since a double crown removable partial denture can be applied without the risk of surgical operation to the medically compromised patients with a poor periodontal condition which is inadequate for dental implants, it has psychological and economical advantages. In this case, there were sufficient remaining teeth to be restored with fixed prostheses in maxilla, while there were a few remaining teeth with a very poor periodontal condition so that it was almost impossible to restore with a clasp removable partial denture using these remaining teeth in mandible. In addition, the patient had the medical history of surgical operation due to osteomyelitis in the mandibular anterior areas a year ago, thus difficult to conduct an implant placement. The main objective of this report is to introduce our case because a double crown partial denture using a few mandibular remaining teeth showed satisfactory results in functional and esthetical aspects during more than two years follow-up period in this unfavorable condition.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.5
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• pp.95-100
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• 2009

The water purification systems have been hardly used for agricultural purpose due to their complicated compositions and high costs for farmers, while only simple filtrations have been applied to irrigation systems in order to prevent the system from clogging problems. This study therefore developed a clean water supplying system, the Filter-Disinfection-Adsorption (FDA) system, especially for greenhouse cultivation of where low quality of water is available. This system has also been produced for providing convenience water to farmers in the areas of no water supply service systems for the purpose of washing their bodies or agricultural machineries after farm work. The FDA system consists of three stages of purification processes with an integral module, including disk and teflon filtrations and Ultraviolet (UV) sterilization processes. Indoor experiments were undertaken with a trial product of the FDA system to test its performance. The operation test of the process was performed as well as the condition check of each item including UV module, filters, control panel, pump, valves, etc. The results shows good performance of each test with no critical problems. The initial and maintenance costs were also analysed with other purification systems. From the comparisons, the FDA system found to be very economical and easy to use.

• Journal of the Korean Institute of Navigation
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• v.24 no.3
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• pp.167-176
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• 2000

The -advent of electronic navigation equipment and trustworthy computer which provides people with convenience made the management system by one-man bridge operation or the least people who are needed possible through the integration of communication network with various navigation equipment and related institution. One of the most needed ultra-modem navigation device for a mate, ECDIS is a core equipment for navigation in ENS that notifies peril to mate as well as supervises all tasks in hydrographical chart, voyage planning, course monitoring and voyage recording. We should make coast and ocean voyage planning first, for the secure navigation which is considering the course circumstances and next, for the reduction of voyage dates in economical aspect. There needs a thoughtful consideration about the feature of the ship itself and the course with weather condition in taking up the course and also we have to take into accounts about appropriate distance between ships. Considering the essential conditions of ECDIS the indispensable device in the future, it was developed the basic principle for voyage planning algorithm for officer and programmed to real implementation available. In this paper including most of the requirements in ECDIS performance standard I mentioned about such a basic and a core Principle with real application by using the Visual C++ programming language. The voyage plan includes the function that indicate and modifies all the way points in the course from department port to arrival port with erasing the wrong way points. Also, it provides in a document form that shows ETA at glance in average speed sailing.

• Journal of Chest Surgery
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• v.2 no.1
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• pp.13-18
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• 1969

A clinical evaluation was done on a total of 41 cases of primary bronchogenic carcinoma, which came to the department of thoracic surgery, Chonnam University Hospital for the period of 5 years from May 1964, and the various factors led the patients to an inoperable stage were searched. The incidence ratio of male to female was 5.8:1 and the age group of fifty and sixty decade occupied 78% of the total. The subjective symptoms of the patients were cough with or without sputum [83%], chest pain or chest discomfort [76%], and a few incidence of bloody sputum and hemoptysis. The histological findings were 40% of squamous cell carcinoma, 35% of adenocarcinoma and 25% of anaplastic carcinoma, including 5 cases of unclassified bronchogenie carcinoma in scalene biopsy. 12 cases [29%] of a total of 41 cases received thoracotomy, but 8 cases among them were operable and 4 cases inoperable. The rest of 29 cases [71%] could not receive thoracotomy because of the various contraindication. 23 cases [70%] out of inoperable 33 cases had wasted time over 2 months duration for an operation owing to physicians` misdiagnosis of bronchogenic carcinoma as pulmonary tuberculosis, chronic lung abscess, asthma, pleurisy, pneumonia. common cold, neuralgia in order. The delaying factors led the patients to an inoperable stage were physicians misdiagnosis of bronchogenic carcinoma due to non-specific symptoms and signs of the patients, old aged patients dependance on herb medicine, and poor economical condition of the patients.

• Journal of Hydrogen and New Energy
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• v.25 no.2
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• pp.139-144
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• 2014

A Fuel Cell is one of the solving to reduce greenhouse gases. Despite the high efficiency and environmental friendly of Household Fuel Cell System it has hardly obtained popularity mainly due to its high prices. In order to encourage use of the system prices and operational expenses need to become economical. In this study, optimization through simulation was conducted to find out the optimal operational condition. As a result of simulation the system is operated with DSS operation from 5 O'clock until 19 O'clock for 13 hours at the constant output of 0.4kW to maximize reduction of energy rate. Furthermore, instead of the domestic system with the rated output of 1kW, rated output of the system should be reduced to 0.4 - 0.6kW which can promote installation of household Fuel Cell System.

• Journal of Surface Science and Engineering
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• v.49 no.5
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• pp.408-415
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• 2016

The offshore structures exposed to harsh corrosive such as the marine environment is essential for the quality management technique throughout the life cycle of initial design, construction and operation. Also, it should satisfy the design life and ensure the safety of the substructure with optimization of design process. This study focused on optimization of design condition for corrosion protection of wind turbine structure and computational analyzing was performed to evaluate the performance of corrosion protection with utilizing practical experimental data. We expect this analytical study contribute to improve the corrosion maintenance stability and economical efficiency of designing wind turbine structures. As a result, the design of cathodic protection system using sacrificial anodes required accurate identification of current density in order to meet the long term design life, which can be seen that a change of structure surface's coating breakdown factor is one of the key influencing factors.