• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.2B
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• pp.105-116
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• 2003

The differentiated service architecture is based on a simple model by applying a per-class service in the core node of the network. However, due to the simplified network behavior, the network structure and provisioning were more complicated. If a service provider wants the dynamic provisioning or better bandwidth guarantee, signaling protocol with QoS parameters or admission control method should be deployed in DiffServ network. However, these methods increase the complexity. Therefore, we proposed DPM2 mechanism for admission control in the DiffServ network. In this paper, we describe and survey the admission control methods that are applicable to IP networks and propose also the dynamic provisioning mechanism based on the bandwidth broker and distributed measurement based admission control and movable boundary bandwidth management to support heterogeneous QoS services in differentiated service networks. For the performance evaluation for proposed mechanism, we used ns-2 simulator.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.05a
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• pp.194-194
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• 2003

The International Agency for Research on Cancer (IARC, 1989) has classified whole diesel exhaust as probably carcinogenic to humans. Diesel exhaust particulate matter (DPM) adsorbs different chemical substances including PAHs and nitroarenes. DPM is emphasized because it is a major component of diesel exhaust, it is suspected of contributing to a health hazard. Diesel exhaust is a complex mixture of carbon particles and associated organics and inorganics, and it is not known what fraction or combination of fractions cause the health effects [cancer effects, noncancer effects (respiratory tract irritation/inflammation and changes in lung function)] that have been observed with exposure to diesel exhaust. In order to identify which chemical classes are responsible for the majority of the observed biological activities, we performed a particular biological/chemical analysis. Respirable particulate matter (PM2.5: <2.5mm) was collected from diesel engine exhaust using a high-volume sampler equipped with a cascade impactor. Particulate oganic matter was extracted by the dichloromethane/sonication method and the crude extract was fractionated according to EPA recommended procedure into seven fractions by acid-base partitioning and silica gel column chromatography. We examined genotoxic potentials of diesel exhaust particulate matter using novel genotoxicity tests, which are rapid, simple and sensitive methods for assessing DNA-damage at the DNA and chromosomal level (comet assay, in vitro MN test and Ames test). Higher genotoxic potency was observed in non polar fractions and several PAHs were detected by GC-MS, such as 1,2,5,6 dibenzanthracene, chrysene, 1,2-benzanthracene, phenanthrene and fluoranthene.

• Journal of the Korea Society for Simulation
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• v.15 no.3
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• pp.93-101
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• 2006

Recently, work-related musculoskeletal disorders (WMSDs) become a hot issue in the industrial fields. To prevent the potential risk of workers, various approaches have been adopted. One of the approaches is to improve the design of product, that of jig (or fixture) and that of workstation in the early stage of the development. 3D simulation technology is known as the powerful method for detecting such problems before constructing the workstation, because it is possible to evaluate the posture of worker using 3D models in a cyber space. It enables to find the unexpected problems and save the time and cost for redesign and rework. This paper introduces a 3D simulation case study of workers in an excavator factory. 3D models of products, jigs were developed with CATIA. The assembly processes were animated in IGRIP and DPM. Finally the various postures of worker were simulated using Human. As a result, some postures were analysed as the risky jobs and the result of simulation was used to improve the system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.9
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• pp.571-577
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• 2017

In this numerical study, the separation efficiency of three-phase separator in an oil-sand plant was studied with various inlet head configurations. The free water knockout (FWKO) vessel was designed with a flow rate of $15.89m^3/day$ (100 bbl/day) and the SOR(stream-to-oil ratio)=3.5 was derived using Stokes' law. For modularization, optimization of the design of the inlet head configuration was performed with parallel-connected dual FWKO vessels. The feed condition of bitumen emulsion was API=17, $T_{in}=150^{\circ}C$ and $P_{in}=50bar$. A mean residence time was determined the time when 95% of the oil and water in FWKO vessel was separated. The combination between the volume of fluid (VOF) and the discrete phase model (DPM) was used to simulate the phase separation phenomenon in a multi-phase separator. Furthermore, in order to calculate multi-phase flow the pseudo-transient method was adopted.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.5
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• pp.949-966
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• 2013

Recently, Wireless Body Area Network (WBAN) has promise to revolutionize human daily life. The need for multiple sensors and constant monitoring lead these systems to be energy hungry and expensive with short operating lifetimes. In this paper, we offer a review of existing work of WBAN and focus on energy-aware management in it. We emphasize that nodes computation, wireless communication, topology deployment and energy scavenging are main domains for making a long-lived WBAN. We study the popular power management technique Dynamic Voltage and Frequency Scaling (DVFS) and identify the impact of slack time in Dynamic Power Management (DPM), and finally propose an enhanced dynamic power management method to schedule scaled jobs at slack time with the goal of saving energy and keeping system reliability. Theoretical and experimental evaluations exhibit the effectiveness and efficiency of the proposed method.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.7
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• pp.29-35
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• 2002

Aeroelastic characteristics of a deployable missile control fin have been investigated. A deployable missile control fin is modeled by a 2-dimensional typical section. Supersonic Doublet-Point method is used for the computation of supersonic unsteady aerodynamic forces and Karpel's Minimum-State approximation is used for the aerodynamic approximation. Root-locus method and time-integration method are used for the linear and nonlinear flutter analyses. For the nonlinear flutter analysis the deployable hinge is represented by a asymmetric bilinear spring and is linearized by using the describing function method. From the flutter analyses, the effects of nonlinear parameters on the aeroelastic characteristics are investigated.

• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.3
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• pp.194-201
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• 2007

As the performance of the mobile terminal becomes higher, the power consumption gradually increases. As a result, power management is one of the most important issues in mobile system with battery. In this paper, we describe an DPM(Dynamic Power Management) using DVS(Dynamic Power Management) as a power management mechanism in Qplus operating system. DVS generally considers a specific device such as CPU, whereas we consider the relations with other hardware components as well as each component. We specially focus on the relation between CPU, memory and LCD devices. We also designs a kernel monitor to collect information to decide the policy for power management. According to the experimental results, the proposed method enables to save much power.

• Journal of computational fluids engineering
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• v.18 no.2
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• pp.9-16
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• 2013

The heat transfer enhancement of heat sink with mist flow is studied numerically by solving the conservation equations for mass, momentum and energy in the continuous and dispersed phases. A Lagrangian method is used for tracing dispersed water droplets in the heat sink and an Eulerian species transport model for air and steam mixture. The continuous and dispersed phases are interacted with the drag and evaporation source terms. The computed results show that addition of evaporating mist droplets enhances the cooling performance of heat sink significantly.

• ETRI Journal
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• v.26 no.1
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• pp.27-37
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• 2004

The architecture in a differentiated services (DiffServ) network is based on a simple model that applies a per-class service in the core node of the network. However, because the network behavior is simple, the network structure and provisioning is complicated. If a service provider wants dynamic provisioning or a better bandwidth guarantee, the differentiated services network must use a signaling protocol with QoS parameters or an admission control method. Unfortunately, these methods increase the complexity. To overcome the problems with complexity, we investigated scalable dynamic provisioning for admission control in DiffServ networks. We propose a new scalable $qDPM^2$ mechanism based on a centralized bandwidth broker and distributed measurement-based admission control and movable boundary bandwidth management to support heterogeneous QoS requirements in DiffServ networks.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.5
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• pp.220-230
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• 2017

In this study we apply and compare a variety of numerical methods for calculating residence time distribution in decay tanks, a major design component in the for reducing N-16 radioactivity. Our research group has used a streamlined method using user-defined particle numbers. However, this streamlined method has several problems, including low exiting particle ratios, particle diminishing, and unphysical time distribution, among others. We utilize three numerical methods to establish residence time and time distribution (streamlined, discrete phase method [DPM], and user defined scalar [UDS]) and subsequently compare the averaged results of each. The three tests demonstrate the flow features within the decay tanks, which are then numerically simulated to enable comparison. We conclude that although each simulation predicts similar time averages, the UDS methodology provides a smoother time distribution and tracer contour plots at specific times.