• Elastomers and Composites
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• v.38 no.2
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• pp.103-121
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• 2003

The application of powerful ultrasound to rubber recycling is a very recent field of study. An ultrasonic field creates high frequency extension-contraction stresses by acoustic cavitation. The breakdown of rubber network occurs primarily around pulsating cavities due to the highest level of strain produced by high-power ultrasound. Stronger reductions of cross-link density were observed at a higher pressure, indicating an important role of pressure during ultrasonic recycling. Visible bubbles were observed during ultrasonic treatment as a proof of acoustic cavitation. Shearing effect has a significant influence on improving the efficiency of ultrasonic treatment. After the ultrasonic treatment, the cross-link densities of NR/SBR blends were lower than those of NR and SBR due to the reduced degree of unsaturation and chemical reactions. Carbon black fillers increase the probability of bond scission during ultrasonic treatment, due to the restricted mobility. The mechanical properties of ground tire rubber (GRT)/HDPE blends were improved by ultrasonic treatment and dynamic revulcanization. Ultrasonic treatment of GRT in the presence of HDPE matrix was found to give better mechanical properties due to the chemical reactions between rubber and plastic phases.

• Korean Institute of Interior Design Journal
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• no.32
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• pp.72-81
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• 2002

Southeast Asian region cruise market is expected to be stable or grow in the near future depending on the region's economy. Star Cruises company, which has entirely dominated the regional market since 1998, has attempted to expand beyond traditional cruise routes in Southeast Asian region and develop new markets in Thailand and Dubai. Such a situation urges Korean shipyards to study on Southeast Asian region based cruise ships. This study is to suggest directions for planning of interior spaces of Southeast Asian region based cruise ships. In order to accomplish this purpose the market situation is analyzed and the adequate ship's tonnage(70,000grt class) is decided. According to mission-based design process the sizes of standard staterooms are set up first and then the sizes of the important structural parts of ship are calculated. Through analyzing the 26 cruise ships of 70,000grt class the kinds, locations and sizes of public rooms are grasped. And we inspect 4 cruise ships of Star Cruises, which are now being operated in Southeast Asian region to understand design characteristics of interior spaces.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.284-290
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• 2009

As the increased importance is placed on the new transit systems owing to the environmental pollution caused by the road traffic congestion, the policy for the introduction of the new transit systems as an alternative solution to ease the heavy burden of the construction expenses is being actively established. Since the explicit recognition of such transit systems and the review on the method of its adoption have been a pressing matter in the light of reducing the pending traffic congestion, the development of the rolling stock systems in modes of new transportation has been made in various ways taking into consideration the regional circumstances to alleviate traffic congestion, and offer a more efficient service with the application of their intrinsic characteristics. Such systems also have been developed as a mix of punctuality for railway systems operating on the runway and flexibility for buses. This paper, therefore, deals in more detail with 3 modes of systems such as low-floor articulated buses, GRT(Guided Rapid Transit) and tram cars, and studies the overseas cases of the operation of those systems involving both negative and positive aspects.

• Journal of Aquaculture
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• v.16 no.4
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• pp.240-244
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• 2003

The primitive gonad development in Paralichthys olivaceus was classified into (ⅰ) primordial germ cell (PGC), (ⅱ) genital ridge type (GRT), (ⅲ) primitive gonad type I (PGT I) and (ⅳ) primitive gonad type II stages. In the control group, PGC was recognizable on the 3rd days after hatching, and the primodial gonad after 24th days, while it was around the 22nd day after hatching in the group exposed to PCBs 3.0 $\mu\textrm{g}$/L for 30 days. Likewise, the progress of kidney development was recognized in four stages; unitubular type of mesonephric duct (UTMD), the branched mesonephric duct (BMD), convoluted tubule formation (CTF) and glomerulus appearing (GA) stage. It was structurally completed between the 25th and 30th day after hatching in two groups. There was no significant difference (p>0.05) in the time scale of development of gonad, and kidney between control and the PCBs - exposed group.

• The Journal of the Petrological Society of Korea
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• v.9 no.4
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• pp.211-237
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• 2000

Major element zoning has been analyzed in garnet porphroblasts obtained from the Grt-St and Ky-Grt-St grade assemblages in Zones I on the northern flank of the Pelham Dome, north central Massachusetts. These porphyroblasts grew during multiple phases of deformation and meta-morphism revealed by the inclusion trail geometry plus the chemical zoning patterns within garnet porphyroblasts. Unusual zoning patterns, including zoning reversals and gradient changes in XMn, zlgzag patterns in Fe/(Fe +Mg) and staircase-shaped patterns in XCa, are coincident with textural truncations and other changes in microstructure within the garnet porphrublasts. Chemical variations in plagioclase, biotite, muscovite and staurolite combined with inclusion trail geometry and petrography reveal that the garnet zoning patterns are modified by combinations of the following. (1) Uni-and divariant reactions involving garnet consumption(Grt+ Chl+Ms=St+Bt+Qtz + $H_2$O) and production(St+Ms + Qtz= Bt+ Grt +A1$_2$$SiO_{5}$ + $H_2$O). (2) Deformation induced episudic ionit dissolution, preferential diffusion and re-distribution during foliation development. (3) P-T changes during growth of the porphyroblasts. The P-T paths combined with petrographic and inclusion trail morphology observations consist of two pattens; (1) heating/compression during NW-SE shortening; and (2) decompression with cooling during NNW-SSE shortening. Based on temperature-time(T-t) geochronological data and late-Paleozoic tectonic model, Alleghanian metamorphism, which is the result of heterogeneous shearing concentrated along the boundary between the Abalone Terrane(Pelham dome) and cover rocks(Bronson Hill Terrane), has produced Ky-St-Ms mineral assemblage during Pennsylvanian(290-300 Ma) in Shutesbury area. However, temperature of alleghanian metamorphism was not high enough to form garnet and staurolite in the Northfiled syncline area. Alleghanian metamorphism has affected only the matrix due to heterogeneous shearing in the study area.

• The Mathematical Education
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• v.41 no.2
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• pp.203-213
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• 2002

In this paper, we introduce the concepts of geometric and arithmetic triangles. Geometric and arithmetic triangles are special types of rational Heron triangles - triangles with rational sides and area. In addition, the theory illustrated in this paper gives certain theorems on the determination of non-right angled geometric and arithmetic triangles. In the meantime, with the help of Mathematica, we compute the sides and area of several triangles(GRT, IGT, RIGT, RAT). Since the material presented in this paper is within the reach of undergraduates, it can attract attention of mathematics students and may also be of interest to the mathematicians. In this content we believe this paper can help undergraduates to have interests in the new world of mathematics.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.26-29
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• 2010

네트워크 대역폭 소모 위주로 발생했던 DDoS 공격이 최근에는 웹서비스 대상 시스템 부하 유발을 통해 가용성을 떨어뜨리는 응용계층에서의 DDoS 공격 위주로 발생하고 있다. 이러한 DDoS 공격에 대응하기 위해 History, IP 분산도, GRT, Behavior 기반 등 다양한 대응 메커니즘이 연구되고 있지만 연구초기 단계에 머물러 있다. 본 논문에서는 Admission Control 기반 DDoS 공격대응 메커니즘을 제안하고, 시스템 개발을 통해 성능을 검증하였다. 제안된 메커니즘은 지금까지 발생한 모든 응용계층 DDoS 공격유형에 대응 가능하며, 기존 Behavior 기반 대응기법은 오탐지 가능성이 있으나 제안하는 메커니즘은 오탐지가 발생하지 않는 장점이 있어, 상용 환경에 바로 적용할 수 있을 것으로 예상된다.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.31-38
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• 1998

Guideway Transportation will provide the break-through to solve the traffic problems, which a lot of big cities have over the world. APM (Automated People Mover) system, Guideway Transportation, is classified by PRT, GRT, and MRT according to the capacity of passenger to be carried by its system. In the Application of PRT (Personal Rapid Transit) system, the enact analysis of the traffic problem on the area to be applied should be preceded. PRT system is characterized by Off-Line and Demand Operation. The Network of PRT system depends on the Load Time and Load Pattern. The operation of PRT system will have move efficient way when it is applied to the network with evenly distributed Load Time and Load Pattern.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.205-210
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• 2004

The PRT(Personal Rapid Transit) system has been being researched and examined to efficiently provide high quality services to passengers against the traffic congestion of the capital region. With concept that PRT differentiated from GRT(Group Rapid Transit), PRT generally is a tracked vehicle system operating with unmanned. The embedded software of PRT Automated Control system generally is comprised of the central software, stations software and vehicle software. The controllers of these software interface to each other using its RF communication antennas. In this paper, each embedded software of the PRT system should be applied to an incremental and systematic test approach technique in the design and implementation phase, because the reliability and safety of the PRT system should be assured

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.5
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• pp.203-209
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• 2006

For $P_B=50,\;{\Delta}T=10K$, Ar=5, Pr=2.36, Le=0.015, Pe=1.26, Cv=1.11, the intensity of solutal convection (solutal Grashof number $Grs=3.44x10^4$) is greater than that of thermal convection (thermal Grashof number $Grt=1.81x10^3$) by one order of magnitude, which is based on the solutally buoyancy-driven convection due to the disparity in the molecular weights of the component A($Hg_2Cl_2$) and B(He). With increasing the partial pressure of component B from 10 up to 200 Torr, the rate is decreased exponentially. The convective transport decreases with lower g level and is changed to the diffusive mode at 0.1 $g_0$. In other words, for regions in which the g level is 0.1 $g_0$ or less, the diffusion-driven convection results in a parabolic velocity profile and a recirculating cell is not likely to occur. Therefore a gravitational acceleration level of less than 0.1 $g_0$ can be adequate to ensure purely diffusive transport.