• Journal of the Korean Geophysical Society
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• v.9 no.4
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• pp.387-395
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• 2006

Nowadays, various digital maps on a reduced scale were drawn in Korea including the topographic series of a nation. Though these digital maps are drawn and revised by using aerial photograph or satellite image, there are some problems that it is difficult to revise or renew the topography and natural feature immediately which changes frequently. As the countermeasures of these problems we use GPS accumbency method, which provides user with convenience and accumbency accuracy which is required to revise and renew digital maps. But acquiring correct position by using GPS only may cause not a few errors because of environmental effect of satellite signal errors that GPS obtains. Although accumulated errors which is the major problem of existing method was diminished owing to the position signal received from satellite which is about 20,183km above, the area that can not receives the signal is occur such as woods and high-rise buildings space. And because of the GDOP (Geometry Dilution of Precision) of GPS satellite and the periodically changing orbit of the satellite, the position calculating problems occur. For settlement of these problems and accurate position determination, DGPS (Differential GPS) is indispensably needed. So, in this study, by adapting Radio Beacon Receiver for marine position determination which is the most convenience method of DGPS methods, we elevated accuracy of modification and renewal of digital map and, having wide application in various measurements, proposed the rapid measurement method about widespread area. In this study, wewant to propose the work scheme of rapid modification and renewal of digital map by using Beacon GPS which is comparatively cheap of all the DGPS methods and which makes it possible to measure independently.

• Agribusiness and Information Management
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• v.11 no.1
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• pp.27-39
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• 2019

Agricultural risks are exacerbated by a variety of factors ranging from climatevariability and change, frequent natural disasters, uncertainties in yields and prices, weakrural infrastructure, imperfect markets and lack of financial services including limited spanand design of risk mitigation instruments such as credit and insurance. Indian agriculture has little more than half (53%) of its area still rainfed and this makes it highly sensitive to vagaries of climate causing unstable output. Besides adverse climatic factors, there are man-made disasters such as fire, sale of spurious seeds, adulteration of pesticides and fertilizers etc., and all these severely affect farmers through loss in production and farm income, and are beyond the control of farmers. Hence, crop insurance' is considered to be the promising tool to insulate the farmers from risks faced by them and to sustain them in the agri-business. This paper critically evaluates the performance of recent crop insurance scheme viz., Pradhan Mantri Fasal Bhima Yojana (PMFBY) and its comparative performance with earlier agricultural insurance schemes implemented in the country. It is heartening that, the comparative performance of PMFBY with earlier schemes revealed that, the Government has definitely taken a leap forward in covering more number of farmers and bringing more area under crop insurance with the execution of this new scheme and on this front, it deserves the appreciation in fulfilling the objective for bringing more number of farmers under insurance cover. The use of mobile based technology, reduced number of Crop Cutting Experiments (CCEs) and smart CCEs, digitization of land record and linking them to farmers' account for faster assessment/settlement of claims are some of the steps that contributed for effective implementation of this new crop insurance scheme. However, inadequate claim payments, errors in loss/yield assessment, delayed claim payment, no direct linkage between insurance companies and farmers are the major shortcomings of this scheme. This calls for revamping the crop insurance program in India from time to time in tune with the dynamic changes in climatic factors on one hand and to provide a safety-net for farmers to mitigate losses arising from climatic shocks on the other. The future research avenues include: insuring the revenue of the farmer (Price × Yield) as in USA and more and more tenant farmers should be brought under insurance by doling out discounts for group coverage of farmers like in Philippines where 20 per cent discount in premium is given for a group of 5-10 farmers, 30 per cent for a group of 10-20 and 40 per cent for a group of >20 farmers.

• The Korean Journal of Air & Space Law and Policy
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• v.1
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• pp.163-191
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• 1989

The accident of the midair collision, passengers' falling or goods' dropping occurs or supersonic aircraft make a sonic boom during their conveying passengers or goods to the destination. The accident in transmit damages the their parties on the surface or their properties. In these cases, the third parties who were harmed to their lives or properties have the right to claim damages against the air carrier who caused them. These matters have become one of the important things since aircraft conveyed passengers and goods. Therefore, it is a great concern to settle these matters by law. But the Safety of the present aircraft has been much increased and the aircraft have become larger in size. Its flight altitude became higher than before. So the relationship of the aircraft to the third parties is much different from that of the earlier aircraft. The air transport is now indispensable to our life. It is not so easy to control these matters. In the early part of 20th century, when the third parties suffered the damage, many European countries made laws on the basis of the principle of liability without fault. But each country had a variety of its own law, and different kinds of difficulties have been brought about. Accordingly, the Rome Convention on Surface Damage (1933, 1952, 1978) has been made and revised. In spite of being revised, it contains many problems, and is not carried into effect world-wide. On the other hand, there are no regulations about the compensation of the third parties damaged in Korean existing laws. In case the damage is brought about to them, it is obviously true that the settlement of the liability of compensation for damage should be made by the general principle on the tort in domestic laws. At this point, it is urgent that we make a special law though the domestic legislation as a preliminary measure before we sign the international convention to save third damaged. It is desirable that we should, for the responsibility of the air carriage for the demage of the third parties on the surface, bring in the theory of the absolute liability in view of the legislation of many conutries. As the aircraft fly in the sky, their flight always contains some danger. It is very difficult to prove the fault, and the operator should suffer the principle of liability without fault or the similiar one. In case the liability without fault will be imposed upon the operator for the damage of the third parties, it is necessary to bring in the liability protection system for the protection and up upbringing of the air carriage. The Burden of danger of the air carriage will be reduced by introducing the system. A domestic legislation measure should be necessarily taken as soon as possible as a legal security measure on these matters.

• Journal of Korean Society of Transportation
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• v.22 no.6
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• pp.17-33
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• 2004

Korea's economic development plans instituted in the 1970's, affected by the growth centered policy and rapid industrialization, have prevailed without having aviation safety management system, along with the safety of the other various means of transportation, settled in its place, and subsequently, the aviation accidents occurred until the beginning of year 2000 have incurred an enormous social expense, not to say of a massive loss of human lives. Especially, with regard to the causal factors of accidents, most of recent accidents have been associated with human factor of airmen, thus, only if this can be detected in advance and prevented, the aircraft accident rate will be reduced by a large margin. Therefore, in order to develope improvement methods on the safety system of civil aviation, in this study, safety management system has been divided into three stages: an advance preventive system, a handling system at an accident's occurrence and a post accident handling system, and thereby improvement methods on aviation safety have been suggested for each stage. The threatening factors agatinst aviation safety have been found to be the absence of management standards and regulations, the indifference to or the lack of the law abiding apirit as major factors, and in order to improve on which, it is required that the settlement of the institutional safety management system should precede, and that the Government and the aviation industry should also make a continuous effort to identify the threatening factors against aviation safety, and to provide incentives for the law abiding spirit and the attitude of giving top priority to safety to spread among all the employees.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.21 no.3
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• pp.103-111
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• 2016

Seasonal dynamics of kelp forest-forming algae, Ecklonia cava population formed following the large-scale disturbance by Typhoon 'Bolaven' in August 2012 were investigated in Jeju Island, Korea. Morphological characteristics, recruits density, mortality rate, total density and biomass were monitored bimonthly from June 2013 to June 2015. Total and longest blade lengths, and individual weight of E. cava showed distinct seasonal trends. Stipe length increased from winter to spring, but did not show increase or reduced from summer to autumn. This indicates that morphological characteristics of E. cava are mainly affected by the change of blades. The optimal temperature for E. cava growth was about $15-18^{\circ}C$ during winter to spring while the growths were inhibited at the water temperature above $20^{\circ}C$ during summer. E. cava exhibited very low recruitment during spring-summer. However, high recruitment was observed on April 2015 when canopy cover was very low due to low density. This indicates that recruitment of E. cava was controlled not by seasonal effects but by physical factors such as canopy and space. The mortality rate of juvenile plants was highest due to their unstable settlement. By June 2015, 34 months after the disturbances, E. cava was almost recovered to the pre-disturbance population size structure. These results suggest that recovery of kelp forest following the large-scale disturbance requires a considerable period of time (more than three years). This study should provide valuable ecological information on management, restoration and protection of kelp species.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.224-234
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• 2017

This paper compares the realities of the salary Peak Policy's status and management processes in Korea and Japan, with the aim of determining the development direction for Korea's salary Peak Policy's. Unlike Japan, which successfully achieved close cooperation between government, firms and workers in implementing the Retirement Age Extension Type salary Peak Policy, Korea experienced many problems due to lack of preparation. In order to rationally develop the salary Peak Policy, the government, firms, and workers must cooperate to increase the policy's efficiency via the following steps. First, gradually increase the proportion of retirement age extension. Second, career development that takes into account the various employment types, flexible working hours and aged workers. Third, development of training programs for senior citizen workers, as well as increasing support for changing of jobs and startups. Fourth, expansion of re-employment after retirement age and ways to make use of the skilled labor. Fifth, increasing work efficiency through bonuses and work evaluation that is specialized for aged workers. This paper argues that such measures are necessary for the co-existence of firms and workers, as well as for improving employment stability and labor market flexibility.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1003-1022
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• 2018

In the current work, a series of three-dimensional finite element analyses were carried out to understand the behaviour of a pre-existing single pile to the changes of the tunnel face pressures when a shield TBM tunnel passes underneath the pile. The numerical modelling analysed the results by considering various face pressures (25~100% of the in-situ horizontal stress prior to tunnelling at the tunnel springline). In the numerical modelling, several key issues, such as the pile settlements, the axial pile forces, the shear stresses have been thoroughly analysed for different face pressures. The head settlements of the pile with the maximum face pressure decreased by about 44% compared to corresponding settlement with the minimum face pressure. Furthermore, the maximum axial force of the pile developed with the minimum face pressure. The tunnelling-induced axial pile force at the minimum face pressure was found to be about 21% larger than that with the maximum face pressure. It has been found that the ground settlements and the pile settlements are heavily affected by the face pressures. In addition, the influence of the piles and the ground was analysed by considering characteristics of the soil deformations. Also, the apparent safety factor of the piles are substantially reduced for all the analyses conducted in the current simulation, resulting in severe effects on the adjacent piles. Therefore, the behaviour of the piles, according to change the face pressures, has been extensively examined and analysed by considering the key features in great details.

• Journal of the Korean GEO-environmental Society
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• v.12 no.10
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• pp.39-49
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• 2011

Recently PBD method, one of acceleration of consolidation methods is used in the soft ground to shorten consolidation time for fast settlement during construction. It is economical and easy to work. Discharge capacity of PBD is sensitive in proportion to thickness of soft ground layer, and drainage of PBD declines due to disturbance effect in surrounding ground by mandrel used for vertical drainage setting and setting machines and type. Also, deviation of discharge capacity is large according to ground condition, construction condition and soil properties. In addition, when embankment loading is not conducted instantly after PBD setting due to rain or lack of embankment material supply, it causes leaving period problems. But cause and analysis of those problems for discharge capacity is lack. So, in this test, ground improvement and discharge capacity is investigated by implementing composite discharge capacity test for analysis of an effect factor of PBD discharge capacity with leaving period. After fixing the vertical drain on a cylindrical cylinder, put churned sample into the cylinder. Then leave 0day, 30day, 60day and 90day. And then, load following the loading step of 30, 70 and 120kPa using a pressure device. As a result, the longer leaving period, discharge capacity is reduced. It is caused by a decrease of discharge area caused by creep transformation moisture absorption of PBD filter after long leaving period.

• Journal of the Korean Geotechnical Society
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• v.38 no.10
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• pp.31-40
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• 2022

This study compares elastic moduli calculated using two stiffness testing methods with different strain ranges to evaluate the stress-settlement characteristics of foundation support layers. Elastic moduli were calculated by the soil stiffness gauge (SSG) in the micro-strain range and the plate load test (PLT) in the medium strain range. To apply the elastic moduli obtained by the two testing methods with different strain ranges to the design and construction of foundation soils, the correlation between each measurement value should be identified in advance. As a result of the comparative analysis of the elastic moduli calculated using the two methods in weathered soil and rock, which are representative support layers in Korea, the calculated elastic moduli differed depending on the types of soil and stress conditions. For various soil types, the static elastic modulus obtained by the PLT was reduced by 56% because of the difference in the strain level of the test compared with the dynamic elastic modulus obtained by the SSG. Therefore, the results show that it is necessary to apply corrections to the stress distribution, stress level, and dynamic effect according to the ground stiffness to effectively use the SSG instead of the PLT.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.3
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• pp.263-278
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• 2022

This paper contains experimental study for the development and performance of TBM backfill material with thixotropic properties. The LW backfill material is widely applied to fill the cavity on the back side of the shield TBM excavation, but has disadvantages such as settlement caused by strength reduction, material separation by groundwater, and reduced plasticity. In this paper, laboratory tests and a model test were conducted to assess the performance of inorganic thixotropic backfill material proposed to improve these problems. The results of laboratory tests show that 1 hr-uniaxial compressive strength of ITB was 12 times higher than LW, and the rate of bleeding of 20 hr was 8.3 times lower, and the result of flow table test was more than 27 times higher. This result indicated that the inorganic thixotropic backfill material has superior properties to LW backfill in terms of strength reduction, material separation, and thixotropy. In the model experiment, a model injection device tester was manufactured and the injection performance and filling rate were verified. When material was injected in the water, it was visually checked whether material separation occurred, and it was confirmed that the filling rate was 96% or more. Comparison results with the test of LW and ITB materials was concluded that ITB can reduce the material separation by groundwater and the occurrence of tunnel cavity.