• The Journal of Asian Finance, Economics and Business
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• v.7 no.8
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• pp.695-704
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• 2020

Bitcoin and other prominent cryptocurrencies have gained much attention since the last several years. Globally known as digital coin and virtual currency, this cryptocurrency is gained and traded within the blockchain system. The blockchain technology adopted in using the cryptocurrency has raised the eyebrows within the banking sector, government, stakeholders and individual investors. The rise of the cryptocurrency within this decade since the inception of Bitcoin in 2009 has taken the market by storm. Cryptocurrency is anticipated as the future currency that might replace the current paper currency worldwide. Even though the interest has caught the attention of users, many are not aware of its opportunities, drawbacks and challenges for the future. Researches on cryptocurrencies are still lacking and still at its infancy stage. In providing substantial guide and view to the academic field and users, this paper will discuss the opportunities in the cryptocurrency such as the security of its technology, low transaction cost and high investment return. The originality of this paper is on the discussion within law and regulation, high energy consumption, possibility of crash and bubble, and attacks on network. The future undertakings of cryptocurrency and its application will be systematically reviewed in this paper.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1936-1939
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• 2002

Much recent attention on wireless technologies s put on topology-less wireless network, in which all nodes an be mobile and can communicate over wireless links, due to its ease of deployment, high flexibility and low expenses. One key in topology-less wireless network is mobile base stations (MBSs), which provides access points or mobile terminals (MTs) to wireless backbone network. MBSs can move to anywhere in accordance with changes in geographical distribution of MTs. They serve as dynamic odes. However, in order to utilize network resources and take full advantage of this topology-less network, MBSs must move to suitable position according to the current tate of network use. Moreover, MBSs have to consider the distance among them to avoid the crash and gap area of MBSs. Therefore, this paper proposes MBS movement algorithm by implementing push-pull method to fulfill the corporation of MBSs and considering the center of covered MTs or centroid to satisfy the MT coverage. From the simulation results, the proposed algorithm increases the performance of system when comparing with the centroid-based algoriom〔7〕, such as coverage area, MT coverage and call drops rate.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.1
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• pp.55-68
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• 2010

IEEE WAVE is going through the final standardization process as the wireless access technology which provides drivers in high-speed vehicles with safety-related information and commercial services This paper presents an application-layer protocol for safe driving assistant service and a service system emulator based on this protocol. The safe driving assistant system includes a construction zone information service and a vehicle crash notification service, an emergency vehicle notification service, a probing service and a dilemma zone decision assistant service. Emulator System design for verifying functions of system, The emulator consists of an emulator server that models the movement of all vehicles and road states and a number of clients that models functional units for OBUs, RSUs, and a traffic control center).

• Journal of Auto-vehicle Safety Association
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• v.12 no.2
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• pp.40-46
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• 2020

Modern traffic accidents are a complex occurrence. Various indicators are needed to analyze traffic accidents. Countries that have been investigating traffic accidents for a long time accumulate various data to analyze traffic accidents. The Korean In-Depth Accident Study (KIDAS) database collected damaged vehicles and severity of injury caused by Collision Deformation Classification code (CDC code), Abbreviated Injury Scale (AIS), and Injury Severity Score (ISS). As a result of the investigation, data relating to the injuries of the occupants can be easily obtained, but it was difficult to analyze human severity based on the information of the damaged vehicle. This study suggests a method to measure the speed change at the time of an accident, which is one of the most important indicators in the vehicle crash database, to help advance KIDAS research.

• Computational Structural Engineering
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• v.7 no.3
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• pp.83-93
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• 1994

To design and study the dynamic performance of safety structures, crash tests are needed. Method to get the angular accelerations at the time of impact by integating the Euler equations are introduced. Numerically stable 9-array system contains several 7 and 8-array sub-systems in it. Numerical stability of those latent sub-systems are studied using test files. All of the 8-array subsystems were found to be numerically stable. Six of the 7-array sub-systems were stable and other six of the 7-array sub-systems were unstable. Using this findings fail-safe measurement system can be developed.

• Interaction and multiscale mechanics
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• v.6 no.2
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• pp.137-156
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• 2013

In this paper, a meshfree shell adaptive procedure is developed for the applications in the sheet metal forming simulation. The meshfree shell formulation is based on the first-order shear deformable shell theory and utilizes the degenerated continuum and updated Lagrangian approach for the nonlinear analysis. For the sheet metal forming simulation, an h-type adaptivity based on the meshfree background cells is considered and a geometric error indicator is adopted. The enriched nodes in adaptivity are added to the centroids of the adaptive cells and their shape functions are computed using a first-order generalized meshfree (GMF) convex approximation. The GMF convex approximation provides a smooth and non-negative shape function that vanishes at the boundary, thus the enriched nodes have no influence outside the adapted cells and only the shape functions within the adaptive cells need to be re-computed. Based on this concept, a multi-level refinement procedure is developed which does not require the constraint equations to enforce the compatibility. With this approach the adaptive solution maintains the order of meshfree approximation with least computational cost. Two numerical examples are presented to demonstrate the performance of the proposed method in the adaptive shell analysis.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.3
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• pp.696-705
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• 2015

Approximately 4,000 vessels including sea trial ships per day are passing, entering or departing from Korea coastal waterway. Sea trial ships have erratic navigating patterns such as quick turning, crash stop and do not communicate with other vessels in appropriate time, so sea trial ships are often to expose dangerous situation such as collision in heavy traffic area. To identify the sea trial vessel's risk factors, this paper surveyed marine traffic volumes for 7 days in Korea harbour & coastal waterway, and it analyzed marine accident rate and intended to identify the risk degree of passing vessels. After that, this researched how many sea trial ship's traffic and what is the sea trial risk among sea trial items. We also conducted survey questionnaire and identified risk factors of sea trial ship. So this paper aimed to enhance the safety of korea coastal waterway to prevent sea trial ship's marine accident.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.3
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• pp.647-655
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• 2014

In this research, unlike other fishing, the diving apparatus fishery is that the diver is engaged in fishing for profits. Because it is unique fishery, conflicts can be occurred in members. So, the purpose of this research is to define the contractual relationship between the parties of the diving apparatus fishery. For example, the relationship between the owner and diver and the owner and fishing ship crew. In addition, civil liability of default on the obligation was reviewed. Also, because the trouble was occurred by illegal fishing, criminal liability of ship crash caused by illegal diving apparatus fishery was considered. As a result, It is important to notifying the necessity of some method for the status of diver and fishing ship crew in diving apparatus fishery. moreover, It is need to educate the risk of illegal fishery for the parties of diving apparatus fishery.

• Journal of The Korean Astronomical Society
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• v.36 no.3
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• pp.111-121
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• 2003

In order to explore the cosmic ray acceleration at the cosmological shocks, we have performed numerical simulations of one-dimensional, plane-parallel, cosmic ray (CR) modified shocks with the newly developed CRASH (Cosmic Ray Amr SHock) numerical code. Based on the hypothesis that strong Alfven waves are self-generated by streaming CRs, the Bohm diffusion model for CRs is adopted. The code includes a plasma-physics-based 'injection' model that transfers a small proportion of the thermal proton flux through the shock into low energy CRs for acceleration there. We found that, for strong accretion shocks with Mach numbers greater than 10, CRs can absorb most of shock kinetic energy and the accretion shock speed is reduced up to $20\%$, compared to pure gas dynamic shocks. Although the amount of kinetic energy passed through accretion shocks is small, since they propagate into the low density intergalactic medium, they might possibly provide acceleration sites for ultra-high energy cosmic rays of $E\ll10^{18}eV$. For internal/merger shocks with Mach numbers less than 3, however, the energy transfer to CRs is only about $10-20\%$ and so nonlinear feedback due to the CR pressure is insignificant. Considering that intracluster medium (ICM) can be shocked repeatedly, however, the CRs generated by these weak shocks could be sufficient to explain the observed non-thermal signatures from clusters of galaxies.

• Korean Parent-Child Health Journal
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• v.10 no.1
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• pp.77-90
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• 2007

Purpose: Motor vehicle crashes are the leading cause of death among children younger than 14 years old. The purposes of this study were to 1) provide a basic overview of child safety seats, 2) review car seat safety usage and misuse, 3) suggest interventions to motivate the usage of child safety seats. Method: The design was a descriptive study with literature review. Previous studies were searched of PUBMED, ProQuest and KERIS. Result: Child safety seats and automobile safety belts protect children in a crash if they are used correctly, but if a child does not fit in the restraint correctly, it can lead to injury. A child safety seat should be used until the child correctly fits into an adult seat belt. Conclusion: To improve child passenger's safety, educational, legislational and environmental enforcements are needed: educational interventions to promote use of child safety seats, strengtened legislation to mandate use of child safety seats, establishment of public acquirements.