• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.785-795
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• 2018

The International Maritime Organization (IMO) has recognized the risk of hull fouling and announced '2011 Guidelines for the control and management of ship's biofouling to minimize the transfer of invasive aquatic species'and is planning international regulations to enforce them in the future. In this study, to effectively respond to future international regulation, we introduce the case of leading countries related to management of hull fouling and also investigate environmental risk assessment techniques for in-water cleaning. Australia and New Zealand, the leading countries in hull fouling management, have established hull fouling regulations through biological and chemical risk assessment based on in-water cleaning scenarios. Most European countries without their government regulation have been found to perform in-water cleaning in accordance with the IMO's hull fouling regulations. In the Republic of Korea, there is no domestic law for hull fouling organisms, and only approximately 17 species of marine ecological disturbance organisms, are designated and managed under the Marine Ecosystem Law. Since in-water cleaning is accompanied by diffusion of alien species and release of chemical substances into aquatic environments, results from biological as well as chemical risk assessment are performed separately, and then evaluation of in-water cleaning permission is judged by combining these two results. Biological risk assessment created 40 codes of in-water cleaning scenarios, and calculated Risk Priority Number (RPN) scores based on key factors that affect intrusion of alien species during in-water cleaning. Chemical risk assessment was performed using the MAMPEC (Marine Antifoulant Model to Predict Environmental Concentrations), to determine PEC and PNEC values based on copper concentration released during in-water cleaning. Finally, if the PEC/PNEC ratio is >1, it means that chemical risk is high. Based on the assumption that the R/V EARDO ship performs in-water cleaning at Busan's Gamcheon Port, biological risk was estimated to be low due to the RPN value was <10,000, but the PEC/PNEC ratio was higher than 1, it was evaluated as impossible for in-water cleaning. Therefore, it will be necessary for the Republic of Korea to develop the in-water cleaning technology by referring to the case of leading countries and to establish domestic law of ship's hull fouling management, suitable for domestic harbors.

• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.975-983
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• 1998

In these days, information communication systems are based on both open distributed computing technologies and object-oriented techniques like inheritance, encapsulation and object reuse to support various system configuration and application. As information systems are interconnected through unsecure networks, the need for the secure information exchange is more critical than before. In this paper, we have designed and implemented a transparent CORBA-basce Security infrastructure with authentication, security context association, access control and security information management to support a secure applications in distributed object environment. SESAME Ver. 4 was adopted as an external security service to manage user privilege attributes and to distribute keys for data encryption, decryption and integrity. Using filter and transformer with an interface to Object Request Broker, it provides a transparent security service to applications. The filter objects are special classes that allow additional parameters to be inserted into messages before they are sent and removed just after they are received. The transformer objects are special classes that allow direct access to the byte stream of every messages for encryption and decryption before it is sent and just after it is received. This study is to implement the access control interceptor(ACI) and the secure invocation interceptor(SII) of secure ORB defined in CORBA using filter and transformer.

• Journal of Korean Society of Transportation
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• v.18 no.5
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• pp.83-97
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• 2000

The traffic management schemes through traffic signal control and information provision could be effective when the link-level data and trip-level data were used simultaneously in analysis Procedures. But, because the trip-level data. such as origin, destination and departure time, can not be obtained through the existing surveillance systems directly. It is needed to estimate it using the link-level data which can be obtained easily. Therefore the objective of this study is to develop the model to estimate O-D demand using only the link flows in highway network as a real time. The methodological approaches in this study are kalman filer, least-square method and normalized least-square method. The kalman filter is developed in the basis of the bayesian update. The normalized least-square method is developed in the basis of the least-square method and the natural constraint equation. These three models were experimented using two kinds of simulated data. The one has two abrupt changing Patterns in traffic flow rates The other is a 24 hours data that has three Peak times in a day Among these models, kalman filer has Produced more accurate and adaptive results than others. Therefore it is seemed that this model could be used in traffic demand management. control, travel time forecasting and dynamic assignment, and so forth.

• Journal of Korean Society of Transportation
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• v.22 no.5
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• pp.123-137
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• 2004

The study on traffic assignment is actively being performed which reflect networks status using time. Its background is increasing social needs to use traffic assignment models in not only hardware area of road network plan but also software area of traffic management or control. In addition, multi-class traffic assignment model is receiving study in order to fill a gap between theory and practice of traffic assignment model. This model is made up of two, one of which is multi-driver class and the other multi-vehicle class. The latter is the more realistic because it can be combined with dynamic model. On this background, this study is to build multidynamic model combining the above-mentioned two areas. This has been a theoretic pillar of ITS in which dynamic user equilibrium assignment model is now made an issue, therefore more realistic dynamic model is expected to be built by combining it with multi-class model. In case of multi-vehicle, FIFO would be violated which is necessary to build the dynamic assignment model. This means that it is impossible to build multi-vehicle dynamic model with the existing dynamic assignment modelling method built under the conditions of FIFO. This study builds dynamic network model which could relieve the FIFO conditions. At the same time, simulation method, one of the existing network loading method, is modified to be applied to this study. Also, as a solution(algorithm) area, time dependent shortest path algorithm which has been modified from existing shortest path algorithm and the existing MSA modified algorithm are built. The convergence of the algorithm is examined which is built by calculating dynamic user equilibrium solution adopting the model and algorithm and grid network.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.3
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• pp.170-177
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• 2006

As a rapid and quick bioactive compound evaluation technique, in this study we utilized a automatic system of High Throughput Screening (HTS) to investigate DPPH radical scavenging efficacy of seaweeds, collected from Jeju Island in Korea. In this study, 6 species of green seaweeds, 18 species of brown seaweeds and 22 species of red seaweeds extracted with methanol at $20^{\circ}C$ and $70^{\circ}C$ were subjected to HTS. Of the green seaweeds tested, Enteromorpha compressa (20G6) of the green seaweeds showed DPPH radical scavenging activity of over 60%. On the other hand, the other green seaweeds showed poor DPPH radical scavenging activities (lees than 40%) at 1 mg/ml. Sargassum siliquastrum (20B17, 70B17), Dictyota dichotoma (70B1), Sargassum coreanum (70B16) and Ecklonia cava (70B26) among the brown seaweeds showed significantly high DPPH radical scavenging activity with 96%, 97%, 92%, 92%, 87%. Polysiphonia japonica (20R24), Schizymenia dubyi (20R17), Gelidium amansii (20R18) and Acrosorium flabellatum (20R23) among the red seaweeds showed remarkable DPPH radical scavenging activity of over 90%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.1
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• pp.124-132
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• 2002

In this paper, we present a vision algorithm and method for input image improvement and preprocessing of dented and raised characters on the sidewall of tires. we define optical condition between reflect coefficient and reflectance by the physical vector calculate. On the contrary this work will recognize the engraved characters using the computer vision technique. Tire input images have all most same grey levels between the characters and backgrounds. The reflectance is little from a tire surface. therefore, it's very difficult segment the characters from the background. Moreover, one side of the character string is raised and the other is dented. So, the captured images are varied with the angle of camera and illumination. For optimum Input images, the angle between camera and illumination was found out to be with in 90$^{\circ}$. In addition, We used complex filtering with low-pass and high-pass band filters to improve input images, for clear input images. Finally we define equation reflect coefficient and reflectance. By doing this, we obtained good images of tires for pattern recognition.

• International Commerce and Information Review
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• v.16 no.1
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• pp.207-226
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• 2014

A trade logistic informatization system under Open Systems Interconnection(OSI) includes a Port Management Information System, a Maritime Information System, and an Export and Import Batch Processing System. These have made a great contribution in the creation of more convenient and efficient management for the logistics industries in our country. However, this management is exposed to the technological problems of networks due to the explosive use in the sending and receiving of e-documents. For our country to grow as a center for port and logistic information, we should make the best use of the control systems using networks and further advance the export and import logistic systems. Therefore, this study aims to propose management systems for a composite network and an invasion detection system for efficient management of an e-trade network under OSI. Methods to rationalize the internal organizations such as coordination of organizations and human resources according to alloted network functions, commissions and arbitrary decisions, and reorganization of relevant regulations are not discussed here. This study looked at trade network under OSI from the aspect of practical business affairs and presented a basis for further interpretation.

• Journal of Engineering Education Research
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• v.10 no.3
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• pp.79-92
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• 2007

To enhance the excellence, effectiveness and economical efficiency in the learning process, we implement a hybrid educational system for engineering experiments where web-based virtual laboratory systems and distance education systems are properly integrated. In the first stage, we designed client/server distributed environment and developed web-based virtual laboratory systems for digital systems and electrical/electronic circuit experiments. The proposed virtual laboratory systems are composed of four important sessions and their management system: concept learning session, virtual experiment session, assessment session. With the aid of the management system every session is organically tied up together to achieve maximum learning efficiency. In the second stage, we have implemented efficient and cost-effective distant laboratory systems for practicing electric/electronic circuits, which can be used to eliminate the lack of reality occurred during virtual laboratory session. The use of simple and user-friendly design allows a large number of people to access our distant laboratory systems easily. Thus, self-guided advanced training is available even if a lot of expensive equipment will not be provided in the on-campus laboratories. The proposed virtual/distant laboratory systems can be used in stand-alone fashion, but to enhance learning efficiency we integrated them and developed a hybrid educational system for engineering experiments. Our hybrid education system provides the learners with interactive learning environment and a new approach for the delivery of engineering experiments.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.113-125
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• 2017

In spite of bulk literature about the tuning of TMD, the effectiveness of TMD in reducing the seismic response of engineering structures is still in a row. This paper deals with the optimum tuning parameters of a passive TMD and simulated on MATLAB with a ten-story numerical shear building. A weighted multi-objective optimization method based on computer experiment consisting of coupled with central composite design(CCD) central composite design and response surface methodology(RSM) was applied to find out the optimum tuning parameters of TMD. After the optimization, the so-conceived TMD turns out to be optimal with respect to the specific seismic event, hence allowing for an optimum reduction in seismic response. The method was employed on above structure by assuming first the El Centro seismic input as a sort of benchmark excitation, and then additional recent strong-motion earthquakes. It is found that the RSM based weighted multi-objective optimized damper improves frequency responses and root mean square displacements of the structure without TMD by 31.6% and 82.3% under El Centro earthquake, respectively, and has an equal or higher performance than the conventionally designed dampers with respect to frequency responses and root mean square displacements and when applied to earthquakes.

• Journal of Wetlands Research
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• v.23 no.4
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• pp.327-341
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• 2021

The riparian eco-belt is an efficient technique that can reduce non-point pollution sources in the basin and improve ecological connectivity and health. In Korea, a legal system for the construction and management of riparian eco-belts is in operation. However, it is currently excluded that rivers and floodplains in dam reservoir that are advantageous for buffer functions such as control of non-point pollutants and ecological habitats. Accordingly, this study presented and analyzed a plan to select a site for an integrated riparian ecol-belt that comprehensively evaluates the water quality and ecosystem characteristics of each dam floodplain and riparian zone for the Daecheong Dam basin in Geum River watershed. First, the Daecheong Dam basin was divided into 138 sub-basin with GIS, and the riparian zone adjacent to the dam floodplain was analyzed. Sixteen evaluation factors related to the ecosystem and water quality impact that affect the selection of integrated riparian eco-belt were decided, and weights for the importance of each factor were set through AHP analysis. The priority of site suitability was derived by conducting an integrated evaluation by applying weights to sub-basin by floodplains and riparian zone factors. In order to determine whether the sites derived through GIS site analysis are sutiable for actual implementation, five sites were inspected according to three factors: land use, pollution sources, and ecological connectivity. As a result, it was confirmed that all sites were appropriate to apply integrated riparian ecol-belt. It is judged that the riparian eco-belt site analysis technique proposed through this study can be applied as a useful tool when establishing an integrated riparian zone management policy in the future. However, it might be necessary to experiment various evaluation factors and weights for each item according to the characteristics and issues of each dam. Additional research need to be conducted on elaborated conservation and restoration strategies considering the Green-Blue Network aspect, evaluation of ecosystem services, and interconnection between related laws and policy and its improvements.