• Journal of the Economic Geographical Society of Korea
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• v.6 no.1
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• pp.211-231
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• 2003

In this study, first, current state and future prospects of indirect real estate investment systems after foreign exchange crisis are analyzed, and second, policy alternatives for activating indirect real estate investment markets are examined. After foreign exchange crisis, various indirect real estate investment systems, such as REITs, ABS and CRC, were introduced. Present market size of indirect real estate investment is not larger than expected. The reasons are the problems of incomplete system on the one hand, and real estate market conditions on the other hand. But long term prospects of indirect real estate investment markets may not be pessimistic. Considering the positive effects of indirect real estate investment systems to the real estate and financial markets, policy supports for activating indirect real estate investment market may be needed. The representative alternatives are reconciliation and integration of indirect real estate investment systems, upgrading the infrastructure of real estate industry, and activating the networks between indirect real estate investment markets and related markets such as financial makets, capital markets, restructuring markets.

• Journal of the Korea Computer Industry Society
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• v.5 no.9
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• pp.1101-1110
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• 2004

In the first quarter of 2004, there were about 1 billion 348 million mobile phone users worldwide with a penetration rate of only 29%. Korea ranks among the highest in the use of mobile communication, having over 36 million mobile phone subscribers with a mobile phone penetration rate of 75% as of May 2004. Since the introduction of wireless Internet service in May 1999, the number of subscribers rose to 34.5 million with 95.3% of the total mobile phone subscribers using wireless Internet services in May 2004, largely due to continued investments by telecommunication service providers, improvement of mobile handsets (color and digital camera phones) and implementation of policies on mobile number portability. In the Korean wireless Internet market, there are many user complaints since the service providers are competing with each other through TV commercial sales and phone discounts rather than improving their call quality, services and billing systems. therefore there is a growing need to improve the billing systems through means such as the implementation of reasonable payment plans according to consumer use, development of a wireless Internet billing system that can predict the number of users and establishment of pricing standards for controlled data (head, tail, etc...) as well as menu information by testing the texts. multimedia, video and other types of content provided by the three major mobile communication companies. The purpose of this study is to promote wireless Internet services and protect user rights by proposing a reasonable way to improve the billing systems for wireless Internet services after conducting a comparative analysis of file size and billing data of each of the service providers through a verification test on a packet billing system for wireless Internet services.

• Journal of Advanced Navigation Technology
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• v.15 no.5
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• pp.687-695
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• 2011

The defect caused by the software industry that is the source of knowledge-centric, information-centric and technology-centric affects an engine which operate a major role for operation of aircraft. Therefore, we should minimize the danger from the defect by strengthening the stability of aviation through the stability analysis of software. In this paper, we examine the laws and systems about the aircraft defects and software safety and propose the enhancement and the enactment of the law or measures to strengthen aviation safety. We should the existing law or system as items, such as the revision related to the safety analysis, standards of quality assurance including safety, application of quality assurance that you must attach the safety analysis report, assessment of detailed instructions of certification authorities. In addition, we should enact the new law and system as items such as the mandatory software evaluation and certification, continuous assessment based on the software life cycle, mandatory introduction of a standardized development methodology, strengthening of advanced workforce system. We can expect the improvement of software quality and an enhanced aviation safety by improving existing laws or systems and enacting new laws or systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.833-842
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• 2020

The purpose of this study is to analyze the economic feasibility of technology developed by the National Institute of Animal Science used to shorten the raising term of Hanwoo cattle. This technology can address the increasing proportion of feed cost to operating expenses in the industry. The technology maintains quality by high nutrition breeding during the growing period while shortening the fattening period compared to conventional methods for castrated cattle. Our analysis employs the partial budget method, and results are as follows. First, we found that the ratio of shipment in age of less than 29 months has been increasing. Second, the statistical test finds that both the reduction in age of the months for shipment and the increase in dressed weight annually are significant. Third, the benefit of introducing the technology with the self-manufactured TMR accounts for 467,990 won per head/time. This result is strong evidence for prioritizing and extending pilot projects. In order to further expand this technology in the future, problems, limitations, and obstacles to introduction should be additionally disclosed for participating and non-participating farms after conducting the pilot project.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.25
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• pp.3-40
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• 2005

Many Korean construction companies have been performing a variety of overseas construction projects since the 1970s. It is unfortunate that in many cases they have had to suffer big losses caused by errors and defects in the design and construction of the projects. In the author's opinion, however, there were losses that could have been avoided if they had understood better the feature and content of the particular construction contract. Few lawyers and scholars in Korea have been interested in the research and study of international construction contracts. This is mainly because they do not have access to practical sources outside of Korea for them to research and study since the contracts undertaken have been dealt with by law firms in other jurisdictions to which the disputes apply. This article is aiming primarily at the introduction of the issues which the practitioners are likely to confront in the process of reviewing and performing the international construction contract. In some cases solutions are sought about these issues based upon the FIDIC standard terms and conditions, the actual experience of practice, and UNIDROIT Principles, etc. It is reasonable to say that all the issues related to the international construction contract cannot be covered in a short article like this. The author wishes this article could induce subsequent studies on international construction contracts for further research. It has to be noted that from time to time Korean construction practices have been compared to the international ones for better understanding. This article mostly includes cases where the Korean construction companies go overseas for their projects, while there are some cases where foreign developers and financial investors participated in domestic projects in which international construction contracts forms were adopted. A few precedent domestic writings about international construction contracts seems to lack emphasis on the points that there are several standard construction contract forms and that they are different. The differences are mainly in accordance with who bears the design responsibility, how the owner has to make progress payments to the contractor and who the funding source for the project is. This article tries to make it clear that there are significant differences between the standard contract forms, e.g. a simple construction form, a design-build form and an EPC/turnkey form of contract. Again, the author hopes that this article can arouse the interest in the international construction contracts from both academic and practical fields, so that many subsequent advanced articles can help our construction industry become much more competitive in the world through awareness of the methods of procurement and administration of the contracts.

• Tunnel and Underground Space
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• v.28 no.3
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• pp.209-231
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• 2018

Severe mine disasters have continued to occur around the world. To ensure worker's health and safety and enhance the productivity, a number of studies have been conducted for the development of wireless sensor network (WSN), environmental monitoring, and communication system in underground mines. An increase in development and application of these systems has just begun with the introduction of information and communication technology into the mining industry in Korea, and yet there have been only a few studies that considered the underground mine ventilation system. This study presented the literature review on the development of WSN and environmental monitoring in underground mines, and especially, on 7 subjects in terms of underground mine ventilation. Moreover, studies that especially conducted real-time environmental monitoring were reviewed and categorized by each commercial software commonly utilized for the ventilation network analysis. For the application in domestic underground mines, further issues were discussed regarding research subjects that may be needed in the future and domestic environmental standards that has been used in the underground mine operation. This paper is expected to be useful for the development of WSN-based environmental monitoring and communication system, as well as for related studies in the future.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.237-241
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• 2010

Many policies have been implemented to mitigate the greenhouse gases in atmosphere overall of sectors. With considering the distinct characteristics of the food security, agricultural sector is no exception to this situation. To this regard, total amount of carbon which is emitted through all of the agricultural production process is calculated, and being based on this result, the demand for the introduction of agricultural production system with low carbon has been rising. Case studies on the application of life cycle assessment (LCA) technique to agricultural sector are found in many countries. For example, life cycle inventory (LCI) data bases of crop, farm infrastructure, fertilizer, farm machinery, and etc., have been constructed and provided by Ecoinvent (Swiss centre for life cycle inventories) of Swiss. In Japan, Top-down typed LCA methodology for agriculture is developed based on the inter-industry analysis, and is evaluated according to the productive method of crop. On the other hand, environmental impact assessment of agricultural system using LCA in Korea is just in the beginning stages. So it is required to assess environmental impact on agricultural fertilizer and pesticide, and to develop their flow modeling, and methodology of LCA of agricultural sector. Environmental impact assessment on agricultural materials, machinery, and infrastructure will also be carried out.

• Journal of the Korean association of regional geographers
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• v.16 no.2
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• pp.100-109
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• 2010

The study examines two different sites to analyze the difference of stream channel profile between two different landuse areas on Neponset River, Boston, MA. Landuse represents the current status of land in terms of human, agricultural or forest, industry and environmental activity types. According to the previous research, forest and urban area are significantly distinguished in chemical characteristic, shape and bed load of the stream. On the chosen sites, I look at the cross-section profile, the slope, velocity, and roughness of the channels. With the data collected at the site I determined the value for the channel bed material using Manning's equation, and compared with the result of HEC-RAS model with the cross-section profile data I measured. In the forest area, water surface elevation and bed material obtained through Manning's equation are very close to HEC-RAS model result. However, in the resident area the Manning's 'n' value calculated much higher than assumption which was considered as cobble whose 'n' value is 0.03-0.06. The difference could be caused by unusual steep elevation on the site and the dam present down further. With the steep elevation upside of dam, there is critical-depth condition occurs. The difference of Manning's 'n' value reflects the difference of depth. HEC-RAS model was run to analyze the difference and the result shows that depth is 0.36 much less than 0.688 what I computed when the Manning's n value is 0.03(cobble) instead of the result of the study (0.13292). Beside, dam is a major source of fragmentation and degradation of stream, and it's possibly inferred upstream water levels are increased and stream velocity is decreased. This study is meaningful for introduction of HEC-RAS in geography field to analyze different sites with channel bed material, and it is going to be used more actively to manage river and river side.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.1
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• pp.1-10
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• 2012

Purpose: Cellulose acetate (CA) was blended with polyethyleneglycol (PEG) having different molecular weight at various mixing conditions to enhance melt-processibility of CA, which might prevent the harmful effect resulted from the introduction of phthalic plasticizer. Methods: To establish optimal plasticizing conditions, CA/PEG blends were examined under various plasticizing conditions: PEG concentration, molecular weight of PEG, and plasticzing temperature. Mechanical properties of the CA/PEG blends, as well as migration and exudation of the PEG, were performed in order to evaluate the efficiency of plasticization. Results: Compared to industrial CA resin plasticized by diethyl phthalate, CA/PEG blends exhibited similar thermal plasticization. It was established that the optimum condition was to blend 30~40 phr PEG with molecular weight 400 at $175{\sim}180^{\circ}C$. CA/PEG blend showed superior glassness, PEG stability, and mechanical properties. Conclusions: CA/PEG blends would be a eco-friendly glasses frame to substitute traditional CA glasses frame prepared phthalate plasticizers.

• Journal of the Korean Professional Engineers Association
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• v.12 no.1
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• pp.12-20
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• 1979

The early history of gun powder (black powder) and explosives was closely connected with the discovery of methods of preparing and purifing salpetre (potassium nitrate KNO$_3$). The Chineses apparently became acquainted with salpetre firstly on about 11th century, and they were possibly the original discoverers of salpetre for raw material of gun powder. The Egyptians called it “Chinese snow”, and it is significant that Chingis-Khan, the Mongol conqueror, took the Chinese eenginees with him in 1218 to use it for attacking the fortifications of the Persian cities. The black powder was invented by chance by Chinese alchemists during the Song dynasty (11th century) in the process of manufacturing medicine, and the powder was introduced to Europe by Mongol army. The manufacturing method of salpetre and gun powder was introduced to Korea from China in 1374, and the powder alld gunnery manufacturing project was developed by Mu Sun Choe(崔茂宣), the first Korean engineer late in Koryo dynasty. Coming in to Yi dynasty the explosive technic, extractive method of salpetre, and gunnery manufacturing process were developed greatly by Mu Sun Choe and Hai Sin Choe (崔海臣). However, confronting with the Japanes invasion at Imjin War (1597) with more powerful western style rifles which had been introduced from the Portuguese, on the contrary Korean army with the traditional guns couldn't compete with them. The Chochong(烏銃, the western rifle introduced in Japane) were much superior to the Chinese style traditional guns in the shooting power and striking efficiency. On the other hand, the Japanese battle ships armed only with the Chochong, when confronted with the Korean turtle shaped ships under the commanding of Admiral Yi Sun-Sin(李舞臣), were defeated by the Korean canons on the ships. The technical development of the modern powder industry in Korea. with the construction of four big explosive plants from 1930 to 1945, has resulted the mass-production of explosives. This study was purposed to investigate to the process with regard to the details of introduction to the explosive technology in Korea, and intended to give a help to the engineers who are engaged in study of the explosive technics by means of giving a spot light data on the early process of the designs, and making suggestion to the researchers for further study and invent a new and modern explosive.