• Membrane Journal
• /
• v.17 no.4
• /
• pp.359-368
• /
• 2007

The copolymer membranes, poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) were prepared by phase inversion method using as an additive with N,N-dimethylformamid as a solvent. The pores are generated during the solvent and non-solvent exchange process in the coagulation bath filled with non-solvent (distilled water). The highest porosity of the membrane was 60%. The surface and cross-section of the membranes was observed with a scanning electron microscopy (SEM). The mechanical property of the membrane was determined by using an universal testing machine (UTM). Tensile strength of measured membranes is presented the maximum 6.57 MPa at 30 wt% of PVdF-HFP.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.2 no.4
• /
• pp.231-238
• /
• 2004

The conditions are obtained for the decomposition of solid radioactive wastes, including ion exchange resin, zeolite, charcoal, and sludge from nuclear power plant. In the process of decomposing the radioactive wastes was used the microwave acid digestion method with mixed acid. The solution after acid digestion by the following method was colorless and transparent. Each solution was analyzed with ICP-AES and AAS and the recovery yield for 5 different elements added into the simulated radioactive wastes were over $94{\%}$. The elemental analysis of destructive low and medium level radioactive wastes by the proposed microwave acid digestion conditions concerning the chemical characteristics of each radioactive waste are expected to be useful basic data for development of optimal glass formulation.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.1
• /
• pp.257-264
• /
• 2012

The development of mobile devices and the spread of wireless network help share and exchange information and resources more easily. The bond them to Cloud Computing technology help pay attention to "Mobile Cloud" service, so there have been being a lot of studies on "Mobile Cloud" service. Especially, the important of 'Recommendation Service' which is customized for each user's preference and context has been increasing. In order to provide appropriate recommendation services, it enables to recognize user's current state, analyze the user's profile like user's tendency and preference, and draw the service answering the user's request. Most existing frameworks, however, are not very suitable for mobile devices because they were proposed on the web-based. And other context information except location information among user's context information are not much considered. Therefore, this paper proposed the context-aware framework, which provides more suitable services by using user's context and profile.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.4
• /
• pp.29-37
• /
• 2013

Multiplayer games typically organized based on a client-server(CS) or peer-to-peer(PP) architecture. The CS architecture is not scalable with the number of players due to a large bandwidth requirement at the server. The PP architecture, on the other hand, introduces significant overhead for the players, as each player needs to check the consistency between its local state and the state of all other players. We then propose a method that combines the merits of CS and PP. In this method, players exchange updates with lower priority in a peer-to-peer manner but communicate directly with a central server for the other updates. As a result, the proposed method has a lower network bandwidth requirement than the server of a CS architecture and the server bandwidth bottleneck is removed. For another important issue about multiplayer games, this method always maintains state consistency among players correctly. The performance of this method is evaluated through extensive simulation experiments and analysis.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.4
• /
• pp.123-130
• /
• 2018

Many massively multiplayer online games(MMOG) use client-server architectures that have enormous server-side bandwidth requirements. In this paper, we propose a region-based hybrid game architecture that combines the advantages of client-server and peer-to-peer architectures, so that only critical events changing game state are processed by the server. In this hybrid architecture, the central server divides the game into regions and assigns a player as a regional server to distribute important updates for that region. Thus, the central server sends state updates to the players through the regional servers. All players in the same region directly exchange updates without affecting game state. This division of labor greatly reduces server bandwidth significantly and enables it to serve larger number of concurrent players. Our experiments show that the region-based hybrid architecture with three-level hierarchy scales better than the client-server architecture, saving considerable bandwidth at the central server while requiring enough bandwidth of players acting as regional servers.

• Journal of IKEEE
• /
• v.24 no.1
• /
• pp.311-318
• /
• 2020

A virtual power plant is a kind of software power plant that enables participation in power operation by integrally managing individual distributed resources. This paper proposes a common information communication architecture based on the TASE.2 standard and the OpenADR2.0 standard to operate a virtual power plant as a single power system. ESS is designed TASE.2 SBO devices that related objects are mapped to OpenADR2.0 services and composed as a single sequence type. Through simulation verification, it conforms data exchange and operation based on both standards.

• Journal of the Korean Chemical Society
• /
• v.57 no.3
• /
• pp.329-334
• /
• 2013

A pine needle-embedded graphite enzyme electrode, of which bonding agent is CSM rubber, was newly designed and its electrochemistry was studied based on the amperometry. It involved a ground green leaves of pine tree as a zymogen together with electrochemical mediator, ferrocene within the paste. The plots of ln($i(1-e^{nf{\eta}})$) vs. ${\eta}$ and Lineweaver-Burk at the low potential (-100 to -500 mV) showed good linearities indicating that the amperometric response is by the catalytic power of pine peroxidase. Electrochemical parameters obtained, symmetry factor (${\alpha}$, 0.17), limiting current ($i_1$, 1.99 $A/cm^2$), exchange current density ($i_0$, $5.86{\times}10^{-5}\;A/cm^2$), Michaelis constant ($K_M$, $1.68{\times}10^{-3}$ M) and many others showed that pine peroxidase discharges the role of catalyst quantitatively on the electrode surface. Those proved that the practical use of pine peroxidase is promising in place of the marketed.

• Journal of the Korean Magnetics Society
• /
• v.18 no.6
• /
• pp.227-231
• /
• 2008

Magnetic and structural properties of CoFeZr alloy films as a function of Zr concentration and magnetoresistive properties of spin valves incorporated with amorphous CoFeZr alloy films have been studied. Magnetization and coercivity of CoFeZr alloy films decreased as the Zr content increased. A single amorphous CoFeZr phase was formed when the Zr content is about above 18 at%. Magnetoresistance ratio and exchange coupling field of spin valves with amorphous CoFeZr were reduced slightly as compared with spin valves with CoFe because the resistance of amophous CoFeZr is higher than that of crystalline CoFe. However, the ${\Delta}{\rho}$ of spin valves with amorphous CoFeZr was improved due to reduction of current shunting.

• Membrane Journal
• /
• v.11 no.3
• /
• pp.109-115
• /
• 2001

Pore-filled ion-exchange membranes in which polypropylene(PP) microporous membrane was used as a nascent membrane were prepared by an in-situ cross-linking technique. Poly(vinylbenzyl chloride)(PVBCI) reacted with piperazine(PIP) or 1,4-diaminobicyclo[2,2,2]octane(DABCO) in a di-methylforamide(DMF) solution was filled in the pores of the microporous base membrane. After gellation the remaining chloromethyl groups were, then reacted with an amine such as trimethylamine to form positively charged, ammonium site. This will produce the pore-filled anion-exchange membrane. It was shown that this simple 2 step procedure gave dimensionally stable, pore-filled membranes in which the MG of polymer gel and degree of cross-linking could be easily controlled by the concentration of PVBCI and cross-linker in the starting DMF solution. Specially, high water permeability (7.8 kg/$m^2$hr, host membrane: PP3, MG: 73%, degree of cross-linking: 10%, crosslinker: PIP) at ultra low pressure(100 kPa) indicates the produced pore-filled membranes is usable as a water softening membrane.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.25 no.2
• /
• pp.161-167
• /
• 2015

In this paper, a novel thermoelectric cooling system utilizing condensed water is introduced and its electrical equivalent circuit model is proposed. The introduced system can deals with the condensed water and improves efficiency by spraying the condensed water on heat sink. The electrical equivalent circuit model is derived by combining the circuit model of the classical thermoelectric cooling system with equation of heat exchange. Because the parameters of the model can be defined from not other experimental data but just the data sheet of the thermoelement, the model can be useful to design and develop the controller of the proposed system. We verify that the proposed model is valid and the introduced system is more efficient than the previous thermoelectric cooling system through simulations.