• Journal of Korea Society of Digital Industry and Information Management
• /
• v.6 no.2
• /
• pp.129-141
• /
• 2010

In network service environment, cultures from diversified fields are easily accessible thanks to the convenient digital content services. Unfortunately, unauthorized access and indiscreet misuse behaviors have deprived content owners of their copyrights. This study suggests an integrity-ensured model applicable for forensic evidence of digital content infringement in network service environment. The suggested model is based on MPEG-21 core components for digital content protection and the system is designed in connection with the components of digital content forensics. Also, the present study suggests an efficient technology to protect and manage computer forensic evidence and digital content by authorizing digital content use and catching infringing logs of authorized users without lag in network environment for the benefit of network security and reliability.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.5
• /
• pp.614-621
• /
• 2007

The fishing boat propulsion system employing the modified stern shape and the tunnel to protect a propeller is developed to increase the cruise speed and reduce he problem resulting from the open propeller accidentally catching the waste net and able on the sea. Using 3 different tunnel types, the model test was performed in the circular water channel and the panel method based on the potential theory is applied to analyze the open water performance of the propeller. In the numerical analysis using he potential-based panel method, it calculates the hydrodynamic interaction between the propeller and the tunnel and evaluates the effect of the tunnel geometry. From the numerical and experimental results differing tunnel geometries, the propulsion efficiency is increased by the larger diameter of the inlet than the outlet of the tunnel and the smaller gap between the propeller tip and the tunnel internal surface. These results provide the information of the propeller system with the tunnel and the hydrodynamic interaction between the propeller and the tunnel.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.27 no.4
• /
• pp.232-237
• /
• 1991

The elementary experiments were conducted in order to improve the quality of trap baits in the southern coastal waters of Korea. 16 kind of natural baits or 11 chemicals amino acids or neucleotides, used for experiments.

• International Journal of Internet, Broadcasting and Communication
• /
• v.13 no.4
• /
• pp.22-29
• /
• 2021

This study evaluates the accuracy of corrective feedback from Grammarly, an online grammar checker, on essays written by cyber university learners in terms of detected errors, suggested replacement forms, and false alarms.The results indicate that Grammarly has a high overall error detection rate of over 65%, being particularly strong at catching errors related to articles and prepositions. In addition, on the detected errors, Grammarly mostly provide accurate replacement forms and very rarely make false alarms. These findings suggest that Grammarly has high potential as a useful educational tool to complement the drawbacks of teacher feedback and to help learnersimprove grammatical accuracy in their written work. However, it is still premature to conclude that Grammarly can completely replace teacher feedback because it has the possibility (approximately 35%) of failing to detect errors and the limitationsin detecting errors in certain categories. Since the feedback from Grammarly is not entirely reliable, caution should be taken for successful integration of Grammarly in English writing classes. Teachers should make judicious decisions on when and how to use Grammarly, based on a keen awareness of Grammarly's strengths and limitations.

• Electronics and Telecommunications Trends
• /
• v.36 no.4
• /
• pp.61-71
• /
• 2021

Navigation satellite systems (GPS, GLONASS etc.) provide three main services, i.e., positioning for location based services, navigation for multi-modal transportation services, and timing for communication and critical infrastructure services. They were started as military systems but were extended to civil service. Navigation satellite navigation system began with GPS in the USA and GLONASS in Russia at nearly the same time. Indian NavIC and Chines BDS announced their FOCs in 2016 and 2020, respectively and European Galileo and Japanese QZSS are catching up others. In these days, Navigation Satellite System, Positioning, Navigation, and Timing services are part of our daily life very closely. They are required for autonomous driving car, Unmanned vehicles like UAV, UGV, and UMV, 5G/6G telecommunications, world financial system, power system, survey, agriculture, and so on. The services among navigation satellite systems are very competitive and also cooperative one another. This article describes the status of these systems and evolution in the technical and service senses, which may be helpful for planning korea positioning system(KPS).

• East Asian Economic Review
• /
• v.25 no.4
• /
• pp.361-401
• /
• 2021

This paper sets up a two agent small open economy with monopolistically competitive firms and catching up with the Joneses to investigate the labor and capital Laffer curve, taking into account aging population along the line of Auray et al. (2016), Galí and Monacelli (2005), and Trabandt and Uhlig (2011). The paper finds that the higher the market power of firms is, the larger the consumption inequality between asset holders and non-asset holders is in the economy with aging population. It also finds that there is room for government to increase the tax revenue by raising tax rates under the economy with higher markup, as households will work more hours to compensate for their loss of labor income to tax hikes. The expected maximum tax revenue is likely to shrink with progressive taxations, since non-asset holders with additional dividend income work less and consume more. The paper finds that the fiscal multiplier decreases with the degree of progressive redistribution.

• The Journal of Fisheries Business Administration
• /
• v.54 no.3
• /
• pp.1-16
• /
• 2023

For the sustainable use of fishery resources as common resources and the mitigation of conflicts with commercial fishermen, it is essential to understand recreational anglers' participation process of environmentally responsible behaviors (ERB). This study intends to show that the effects of recreation specialization on environmentally responsible behaviors can be weakened due to the characteristics of anglers, who prefer to possess caught fish. Two different research models were tested with two data sets independently collected. The data were analyzed with structural equation modeling. The results show that consumptive orientation, which measures a degree of catching and owning fish, and fishing-specific ERBs negatively affect the relationships between recreation specialization and general ERBs as mediation variables. Implications are further discussed that regulation policies and education programs are needed to change anglers' consumptive orientation and catch-related fishing behaviors.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.14 no.2
• /
• pp.63-68
• /
• 1978

A boat seine has been used as a major fishing gear for catching anchovy (Engraulis japonica) in the southern coastal waters of Korea since the 1920s. Since the 1950s some improvement from the original seine has been made; powered boats equipped with net hauler has been used instead of rowing boats with hand-driven capstan, and the seining method has been changed into the trawling method. But even now, there are many problems to be solved in the view point of decreasing man power without decreasing catching efficiency. For the purpose, patti-net has been introduced from Japan and experimented on the commercial base since 1972, and it was known that the patti-net could be operated with man power as half as needed in the coventional net, but catching efficiency was not so desirable. Therefore, the study on the characteristics of it were required. The authors carried out a model experiment with a Qne-twentieth scale model net towed by a powered boat on the sea. The obtained results run as follows: 1. Hydrodynamic resistance of the model net can be explained as $R_p=69.6 V_{I.66}$ $R_h=37 v^2$ where $R_p$ and $R_b$ denote the resistance of the whole gear and the cod end in kg respectively, and v the towing speed in mlsec. 2. Performance of wing and cod end showed no deformation such as observed at the conventional net. 3. The ratio of opening at the entrance of bag net to that of cod end showed about 2: 1. Therefore, when we intend to enlarge the net to be able to operate in the deep fishing ground, the cod end should be enlarged in the same proportion and increased towing power is needed .. Then, it will be better to increase the ratio for increasing fishing efficiency without increasing towing power.

• Journal of the Korea Computer Graphics Society
• /
• v.24 no.3
• /
• pp.73-81
• /
• 2018

In this paper, we present a motion-driven rowing simulation framework that allows multiple players to row a boat together by their harmonized movements. In the actual rowing game, it is crucial for the players to synchronize their rowing with respect to time and pose so as to accelerate the boat. Inspired by this interesting feature, we measure the motion similarity among multiple players in real time while they are doing rowing motions and use it to control the velocity of the boat in a virtual environment. We also employ game components such as catching an item which can accelerate or decelerate the boat depending on its type for a moment once it has been obtained by synchronized catching behaviors of the players. By these components, the players can be encouraged to more actively participate in the training for a good teamwork to produce harmonized rowing movements Our methods for the motion recognition for rowing and item catch require the tracking data only for the head and the both hands and are fast enough to facilitate the real-time performance. In order to enhance immersiveness of the virtual environment, we project the rowing simulation result on a wide curved screen.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.31 no.4
• /
• pp.340-349
• /
• 1995

There are several problems in a fishing by the midwater pair trawl net which is used in Denmark; steeply decreasing of the net height with the towing speed increasing, the larger volume of the fishing gear in comparison with the size of the trawler, and catching of a float in a mesh, etc. To prevent steeply decreasing of the net height with the towing speed increasing and catching of a float in a mesh, it is sometimes more useful to use the kite instead of floats. This paper describes the hydrodynamic drag and the opening efficiency of the midwater pair trawl net and the midwater kite pair trawl net obtained by the model test in the circulation water channel. The results can be summarized as follows; 1. The hydrodynamic drag of the midwater kite pair trawl net is about 0.7 times smaller than that of the midwater pair trawl net. 2. The net height, mouth area and filtering volume of the midwater kite pair trawl net are smaller then those of the midwater pair trawl net when the towing speed is below 2.5knots, almost the same at 2.7knots, and are larger over 3.0knots. The net width of the midwater kite pair trawl net is same as that of the midwater pair trawl net. 3. The shapes of net mouth of both net are an oval steeply flatted with the towing speed increasing. The filtering volume of the midwater kite pair trawl net is larger then that of the midwater pair trawl net by 3% at 3.0knots, 11% at 4.0knots, and 16% at 5.0knots respectively.