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Geometry optimization of a double-layered inertial reactive armor configured with rotating discs

  • Bekzat Ajan;Dichuan Zhang;Christos Spitas;Elias Abou Fakhr;Dongming Wei
    • Advances in Computational Design
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    • v.8 no.4
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    • pp.309-325
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    • 2023
  • An innovative inertial reactive armor is being developed through a multi-discipline project. Unlike the well-known explosive or non-explosive reactive armour that uses high-energy explosives or bulging effect, the proposed inertial reactive armour uses active disc elements that is set to rotate rapidly upon impact to effectively deflect and disrupt shaped charges and kinetic energy penetrators. The effectiveness of the proposed armour highly depends on the tangential velocity of the impact point on the rotating disc. However,for a single layer armour with an array of high-speed rotating discs, the tangential velocity is relatively low near the center of the disc and is not available between the gap of the discs. Therefore, it is necessary to configure the armor with double layers to increase the tangential velocity at the point of impact. This paper explores a multi-objective geometry design optimization for the double-layered armor using Nelder-Mead optimization algorithm and integration tools of the python programming language. The optimization objectives include maximizing both average tangential velocity and high tangential velocity areas and minimizing low tangential velocity area. The design parameters include the relative position (translation and rotation) of the disc element between two armor layers. The optimized design results in a significant increase of the average tangential velocity (38%), increase of the high tangential velocity area (71.3%), and decrease of the low tangential velocity area (86.2%) as comparing to the single layer armor.

A Study on the Utilization and Problems of Online Dispute Resolution : Focusing on the Online Arbitration (온라인분쟁해결의 활용과 문제점에 관한 연구 - 온라인중재를 중심으로 -)

  • Yu, Byoung-Yook
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.19
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    • pp.191-223
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    • 2003
  • Electronic commerce and the Internet offer unprecedented opportunities. The explosive expansion of the use of the Internet makes it possible for businesses to expand their markets and render services. Global transaction costs are easy to cut off using Internet and transaction speed is faster than before. Where cyberspace is not free from claims, Offline transaction can lead to problems and disputes the same is for cyberspace transactions. However ADR is not meet for the online transaction for speed, cost and open network system, ODR methods to resolve electronic commerce conflicts is crucial for building confidence and permitting access to justice in an online business environment. The use of the Internet and the network in dispute resolution has an impact on the types of communication implied in the relevant processes such as automated negotiation, online mediation and online arbitration and involves new technological issues such as the integrity and confidentiality of data and communication used to transmit and store data. Among the ODR systems Online Arbitration is currently binding both parties disputed and can achieve the aim of dispute award the same as the traditional arbitration. Arbitration is based on the New York Convention 1958, Arbitration Model law 1985 and national Arbitration Act that are founded on territorial area and rested on arbitration agreement, constitution of the arbitral tribunal, due process, final and binding award and enforcement of the arbitration award. To compare with this issues Online arbitration has unnecessarily legal unstability and risk. ODR is the burgeoning field and has created a new issues. All such issues which have been debated in the ADR are composed with ODR. But these are not limited Some of issues are further complicated by the nature of the online environment such as confidentiality and principle of parties. It is true that online arbitration should comply with legal provisions, but which is impossible to adhere of the law. Flexible translation and functional equivalence of legal provisions are needed for acceptance of electronic commerce disputes. Finally electronic commerce now takes place on the Internet, it is inevitable that the commercial world wants access to dispute resolution process that best suits the new commercial environment. ODR methods are processing for development and legal issues are considered by both national and international authorities. Introduction of new Conventions or amend Convention and Model law of ODR comes near.

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Distributed Contents Delivery Network based on Home gateway for a Sustainable Service (안정적인 서비스를 위한 홈 게이트웨이 기반의 분산 컨텐츠 전송 네트워크)

  • Kim, Myung-Won;Yoon, Young-Hyo;Ko, Joong-Sik;Kwak, Hu-Keun;Chung, Kyu-Sik
    • The KIPS Transactions:PartA
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    • v.15A no.5
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    • pp.249-258
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    • 2008
  • DCDN(Distributed Contents Delivery Network) as known the next generation of CDN is to exploit the resource of client PCs based on P2P technology to provide low cost, high scalability and high speed services when contents are delivered. This DCDN has two problems. One is that DCDN can't provide a sustainable service because client PCs are on/off irregularly and their on times tend to focus on specific time zone, and the other is that client PCs can not be accessed outside in DCDN if they are behind NAT or Firewall. In this paper, we present a distributed contents delivery network based on home gateway for a sustainable service. If home gateway is used in DCDN instead of client PC, it can solve the two existing problems of DCDN. That is, home gateway can provide a sustainable service because it is on during all day and it is not behind NAT and Firewall. The proposed method is implemented with ASUS WL-500GP, a wired/wireless router. Experimental results show the effectiveness of the proposed method compared to the existing method of DCDN.

A High Performance Flash Memory Solid State Disk (고성능 플래시 메모리 솔리드 스테이트 디스크)

  • Yoon, Jin-Hyuk;Nam, Eyee-Hyun;Seong, Yoon-Jae;Kim, Hong-Seok;Min, Sang-Lyul;Cho, Yoo-Kun
    • Journal of KIISE:Computing Practices and Letters
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    • v.14 no.4
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    • pp.378-388
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    • 2008
  • Flash memory has been attracting attention as the next mass storage media for mobile computing systems such as notebook computers and UMPC(Ultra Mobile PC)s due to its low power consumption, high shock and vibration resistance, and small size. A storage system with flash memory excels in random read, sequential read, and sequential write. However, it comes short in random write because of flash memory's physical inability to overwrite data, unless first erased. To overcome this shortcoming, we propose an SSD(Solid State Disk) architecture with two novel features. First, we utilize non-volatile FRAM(Ferroelectric RAM) in conjunction with NAND flash memory, and produce a synergy of FRAM's fast access speed and ability to overwrite, and NAND flash memory's low and affordable price. Second, the architecture categorizes host write requests into small random writes and large sequential writes, and processes them with two different buffer management, optimized for each type of write request. This scheme has been implemented into an SSD prototype and evaluated with a standard PC environment benchmark. The result reveals that our architecture outperforms conventional HDD and other commercial SSDs by more than three times in the throughput for random access workloads.

The Nonlinear Motions of Cylinders(I) (주상체의 비선형 운동(I) -강제동요문제, 조파저항문제-)

  • H.Y. Lee;J.H. Hwang
    • Journal of the Society of Naval Architects of Korea
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    • v.29 no.4
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    • pp.114-131
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    • 1992
  • In the present work, a two-dimensional boundary-value problem for a large amplitude motion is treated as an initial-value problem by satisfying the exact body-boundary and nonlinear free-surface boundary conditions. The present nonlinear numerical scheme is similar to that described by Vinje and Brevig(1981) who utilized the Cauchy's theorem and assumed the periodicity in the horizontal coordinate. In the present thesis, however, the periodicity in the horizontal coordinate is not assumed. Thus the present method can treat more realistic problems, which allow radiating waves to infinities. In the present method of solution, the original infinite fluid domain, is divided into two subdomains ; ie the inner and outer subdomains which are a local nonlinear subdomain and the truncated infinite linear subdomain, respectively. By imposing an appropriate matching condition, the computation is carried out only in the inner domain which includes the body. Here we adopt the nonlinear scheme of Vinje & Brevig only in the inner domain and respresent the solution in the truncated infinite subdomains by distributing the time-dependent Green function on the matching boundaries. The matching condition is that the velocity potential and stream function are required to be continuous across the matching boundary. In the computations we used, if necessary, a regriding algorithm on the free surface which could give converged stable solutions successfully even for the breaking waves. In harmonic oscillation problem, each harmonic component and time-mean force are obtained by the Fourier transform of the computed forces in the time domain. The numerical calculations are made for the following problems. $\cdot$ Forced harmonic large-amplitude oscillation(${\omega}{\neq}0,\;U=0$) $\cdot$ Translation with a uniform speed(${\omega}=0,\;U{\neq}0$) The computed results are compared with available experimental data and other analytical results.

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The Effects of 8-week Ketone Body Supplementation on Endurance Exercise Performance and Autophagy in the Skeletal Muscle of Mice (8주 케톤체 투여가 마우스 지구성 운동수행능력과 골격근의 자가포식에 미치는 영향)

  • Jeong-sun Ju;Min-joo Park;Dal-woo Lee;Dong-won Lee
    • Journal of Life Science
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    • v.33 no.3
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    • pp.242-251
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    • 2023
  • The purpose of this study was to investigate the effects of 8-week β-hydroxybutyrate (β-HB) administration with and without endurance exercise training on endurance exercise performance and skeletal muscle protein synthesis and degradation using a mouse model. Forty-eight male wild-type ICR mice (8 weeks old) were randomly divided into four groups: sedentary control (Sed+Con), (Sed+Con), sedentary β-HB (Sed+β-HB), exercise control (Exe+Con), and exercise β-HB (Exe+β-HB). β-HB was dissolved in PBS (150 mg/ml) and injected subcutaneously daily (250 mg/kg) for 8 weeks. Mice performed 5 days/week of a 20 min treadmill running exercise for 8 weeks. The running exercise was carried out at a speed of 10 m/min at a 10° incline for 5 min, and then the speed was increased by 1 m/min for every 1 min of the remaining 15 min. Following 8 weeks of treatments, visceral fat mass and skeletal muscle mass, blood parameters, and the markers for autophagy and protein synthesis were analyzed. The data were analyzed with one-way ANOVA (p<0.05) using the SPSS 21 program. Eight weeks of Exe+β-HB treatment significantly lowered blood lactate levels compared with the other three groups (Sed+Con, Sed+β-HB, and Exe+β-HB) Exe+β-HB) (p<0.05). Eight weeks of Exe+β-HB significantly increased maximal running time (time to exhaustion) compared with the Sed+Con and Exe+Con groups (p<0.05). Eight weeks of β-HB administration significantly decreased autophagy flux and autophagy-related proteins in the skeletal muscle of mice (p<0.05). Conversely, the combined treatment of β-HB and endurance exercise training increased protein synthesis (mTOR signaling and translation) (p<0.05). The 8-week β-HB treatment and endurance exercise training had synergistic effects on the increase in endurance performance, increase in protein synthesis, and decrease in protein degradation in the skeletal muscle of mice.