• Journal of the Korean Institute of Navigation
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• v.23 no.4
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• pp.43-61
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• 1999

To ensure ship's safety and preserve the marine environment from ship, IMO(International Maritime Organization) has been making much efforts. Nevertheless there are still many possibilities threatening ship's safety and the marine environment. Many vessels navigate at sea in lack of standard required by the International Convention relevant to ship's safety and the protection of marine environment. Even though the administration is responsible for perfect and continuous control for safety of ship, it cannot has jurisdiction over ships hoist its flag reasonably at all times. So the Port State has strengthened the Port State Control(PSC) activity as one step of eliminating sub-standard vessels. In the light of the fact that mentioned above, this study deals with PSC activity in Korea and port of Pusan. Total 582 ships, inspected in port of Pusan from 1st January 1998 to 30th September 1999, were analyzed in various aspect and extracted results as follows : \circled1 The inspection rate in Korea was much lower than the other states taking part in Tokyo MOU, \circled2 For flag state, the ships belong to flag of convenience(FOC) had much more deficiencies than non-convenience flag ships, \circled3 For ship type, 39 number of general dry cargo ship were detained at Pusan with serious deficiencies, \circled4 For deficiency item, the items such as life saving appliances, safety in general, navigation, load lines and fire-fighting appliances were occupied over 71.7% of total number of deficiencies, \circled5 In Asia-Pacific region, Korea was one of flags with detention percentages exceeding 3-year(1996~1998) rolling average detention percentage. Average detention rate of Korean vessels was 6.73% which was over 0.24% of average detention rate(6.49%) in Asia-Pacific region. These results may reflect to improve the performance of PSC inspection for foreign vessels and are useful for preparing PSC inspection for ocean-going ships registered in Korea.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.4
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• pp.691-700
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• 1994

A power line in not so good in characteristics for communication, because it is a media to transfer the commercial electrical power, and its load noise and high frequency noise are so much. Thus, a simple method to transfer a remote control signal on the power line is studied. The already-existing method is that two signals with upper part eliminated is transmitted every N step. But the method is investigated which the transmitter sends a period signal eliminated in arbitrary phase. Thus the transmission power loss due to elimination of signal can be reduced to the minimum. To implement it, a timer calculating the time from zero-crossing point to the phase is required. The micro-controller, 87C51, precisely calculates the phase using one of two built-in timers. As a result, a remote control signal tramsmitter and receiver using a partially eliminated signal, which is better than the conventional technique using half-eliminated signal in a efficiency of power transmission, is realized, and its characteristics are analyzed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.4
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• pp.330-336
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• 2004

To meet the increasing demand from various fishing fields for training of fishing equipment operators, a fishing winch simulator was designed to train maritime students in the correct and safe operation of hydraulic winches under various load conditions related to fishing operations. The aim of this study is to describe the basic dynamic characteristics of the newly developed hydraulic fishing winch simulator and particularly to analyze the mechanical responses produced on the winch operation controls. The winch simulator consists of two winch units, a computer control and data acquisition system, a control consol and other associated mechanisms. When one winch is in hauling mode, the other one will always be in loading mode. The revolution speed of the hauling winch was controlled by a proportional directional control valve, and the braking torque of the loading winch was controlled by a proportional pressure control valve. The simulation experiments indicated that the dynamic characteristics of the hauling winch followed the braking response characteristics of the loading winch. The tests also showed that the warp speed and tension linearly depend on the pressure differential across the motor of the loading winch controlled by operating the proportional pressure control valve during the hauling operation. The experience gained from various training courses showed that the fishing winch simulator was very realistic and it was valuable for training novice winch operators. The results of the winch simulation exercise were recorded and used to evaluate the training on the operation and handling of the winch system. From these test results, we concluded that the tension acting on the warp during hauling operations can successfully be simulated by controlling the pressure differential across the motor with step changes of the control input signal to the proportional pressure control valve of the loading winch.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.3
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• pp.297-311
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• 1998

Landscaping on artificial ground is currently served as a means to imposing a greenery benefit on high-density and high-rise apartment sites. It functions as a sub-hierarchy in apartment planning such as ornamental element from the past. Major parking space tends to be allocated on the basement area in response to the required parking regulation. Therefore, competitive relatioinship between the parking and greenery space I limited outdoor of apartments leads to the development planning strategy and technology of artificial ground. This study aims at evaluating landscape planning on artificial ground of apartment complex through several approaches such as site survey, plan drawing analysis, and interview with related field experts. 15 survey apartment sites including Bundang Model, Shindaebang-dong, Pyoungchon Hyundai Apartments have been selected for conducting the research. Main results of this study are summarized below : First, scattering allocation of artificial ground between apartment building units is a dominant plan layout type among the survey sites. Even though unifying allocation type has an advantage to maximize underground parking space, it has a difficulty in maintaining proper soil ground base for nurturing plants. Therefore, underground parking space should be planned by unifying allocation type placed separately from apartment units. This plan type can provide a balanced planting between soil and artificial ground on surface level. Second, It is strongly recommended to integrate the whole planting base which involves architectural structure, drainage, and water proofing above the planting design. When considering that process as a professional subject dealing with natural material such as trees and shrubs, those tasks should be directed by landscape architectural divison and landscape architect. And planting area for artificial ground has to be specified in initial phase of architectural design. This step provides an opportunity to make a proper decision on structural load, drainage, and water proof design as an integrated part of the management.

• Nuclear Engineering and Technology
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• v.25 no.4
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• pp.552-560
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• 1993

In this study, the detailed fuel assembly stress analysis model to evaluate the structural integrity for seismic and blowdown accidents is developed. For this purpose, as the first step, the program MAIN which identifies the worst bending mode shaped fuel assembly(FA) in core model is made. And the finite element model for stress calculation of FA components is developed. In the model the fuel rods (FRs) and the guide thimbles are modelled by 3-dimensional beam elements, and the spacer grid spring is modelled by a linear and relational spring. The constraints come from the results of the program MAIN. The stress analysis of the 16$\times$16 type FA under arbitary seismic load is performed using the developed program and modelling technique as an example. The developed stress model is helpful for the stress calculation of FA components for seismic and blowdown loads to evaluate the structural integrity of FA.

• Fire Science and Engineering
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• v.23 no.3
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• pp.11-16
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• 2009

This paper describes a detecting method for indication of an electric accident in electric equipments. For that, loads of electric equipment is consisted of incandescent lamps. And the electric accident is simulated a tracking test apparatus according to KS C IEC (Korea Standard C International Electrostatic Commission) 60112 at some part of the simulation of the electric equipment. Simulated electric accident is occurred from static states through discharge in progress, carbon formation to tracking breakdown. The total current of electric equipments is measured and analyzed for detecting of indication of the electric accident using a current monitor. For the result, as an electric accident processed, as a current pulse is bigger and a ratio of appearance also increases at certain part of current waveforms. And standard deviation and probability distribution for certain part of current waveforms show remarkably different pattern in each step of electric accident which is irrespective of amount of load.

• The KIPS Transactions:PartD
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• v.16D no.1
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• pp.93-104
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• 2009

Modular implementation of a feature is a first step toward feature-oriented product line engineering, which develops and then utilizes core assets to configure products in terms of features. Aspect-oriented programming provides effective mechanisms for improving the modularity of feature implementations. However, as features in general are not independent of each other, changes in the implementation of one feature may cause changes to or side effects in the implementation of other features. Moreover, since the time at which a feature is incorporated into products, called feature binding time, may be various from compile time through load time to run time, a feature may have to be implemented differently depending on when the feature is bound into a product. To make each feature implementation module as independent as possible, this paper proposes aspectual implementation patterns that can effectively separate feature dependencies as well as feature binding time from feature implementation modules. These patterns enable flexible composition of feature implementation modules without affecting other modules according to feature selection. The approaches are demonstrated and evaluated based on a product line of scientific calculator applications.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.188-188
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• 2016

The Mekong which is one of the world's most significant rivers plays an extremely important role to South East Asia. Lying across six riparian countries including China, Myanmar, Thailand, Laos, Cambodia and Vietnam and being a greatly biological and ecological diversity of fishes, the river supports a huge population who living along Mekong Basin River. Therefore, much attention has been focused on the giant Mekong Basin River, particularly, the soil erosion and sedimentation problems which rise critical impacts on irrigation, agriculture, navigation, fisheries and aquatic ecosystem. In fact, there have been many methods to calculate these problems; however, in the case of Mekong, the available data have significant limitations because of large area (about 795 00 km2) and a failure by management agencies to analyze and publish of developing countries in Mekong Basin River. As a result, the Universal Soil Loss Equation (USLE) model in a GIS (Geographic Information System) framework was applied in this study. The USLE factors contain the rainfall erosivity, soil erodibility, slope length, steepness, crop management and conservation practices which are represented by raster layers in GIS environment. In the final step, these factors were multiplied together to estimate the soil erosion rate in the study area by using spatial analyst tool in the ArcGIS 10.2 software. The spatial distribution of soil loss result will be used to support river basin management to find the subtainable management practices by showing the position and amount of soil erosion and sediment load in the dangerous areas during the selected 56- year period from 1952 to 2007.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.73-79
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• 2018

In the west coast, south coast, and river basin, the use of geotextile mats has been increasing to improve the soft ground for making industrial facilities space and farmland. As an initial step to improve the vast and soft ground, the geotextile mats are laid and bonded to increase the bearing capacity of the wide ground for supporting construction equipment. Seam strength of geotextile mats exert a force only about 50% of the tensile strength of the fabric, which causes problems such as uplift and sinking in the soft ground. In this study, various types of geosynthetic matting techniques were investigated and the tensile strength of each method was compared and analyzed. Numerical analysis shows that stress increment in the ground due to the overburden load decreases when the seam strength of the geosynthetics mats is increased. When the seam strength was increased to 60, 70 and 80%, the bearing capacity of ground by geotextile mat was increased.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.4
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• pp.16-25
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• 2019

Recently, due to labor shortages in rural areas within South Korea, the demand for upland-field machinery is growing. In addition, there is a lack of development of systematic performance testing of upland-field machinery. Thus, this study examined structural safety and drawbar pull based on soil properties, as a first step for systematic performance testing on the test bed. First, the properties of soil samples from 10 spots within the experimental site were examined. Second, the strain was measured and converted into stress on 8 points of an onion harvester that are likely to fail. More specifically, the chosen parts are linked to the power, along with the drawbar pull, using a 6-component load cell equipped between the tractor and the onion harvester. The water content of the soil ranged between 5.7%-7.5%, and the strength between 250-1171 kPa. The test soil was subsequently classified into loam soil based on the size distribution ratio of the sieved soil. The onion harvester can be considered as structurally safe based on the derived safety factor and the drawbar pull of 115-1194 kgf, according to the working speed based on agricultural fieldwork.