• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.187-190
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• 2006

TETRA system provides the radio authentication service which permits only authorized radio to access network. Radio authentication is the process which checks the sameness of authentication-key(K) by challenge-response protocol between radio and authentication center. This paper analyzes authentication-key generation/delivery/injection model in TETRA authentication system and analyzes the threat of clone radio caused by authentication-key exposure.

• Bulletin of the Korean Chemical Society
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• v.17 no.4
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• pp.334-338
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• 1996

Tetra-chlorodibenzo-p-dioxins (tetra-CDDs) were prepared by microscale pyrolysis of trichlorophenates. During the pyrolysis reaction, tri-, di-, and mono-CDDs were also formed by the thermolysis of tetra-CDDs. The dechlorination pathways of tetra-CDDs were suggested for this reaction. The identification of these products was performed with capillary column gas chromatography-mass spectrometry.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.51-56
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• 2014

TETRA(TErrestrial Trunked RAdio) provide specialized disaster radio communication services as a standard European for digital TRS(Trunked Radio System). Especially, DMO(Direct Mode Operation) feature is used effectively in the radio shadow areas which base station does not propagate radio signal because it can communicate directly with terminal to terminal without base station's relay function. However, to effectively used DMO feature, radio coverage prediction information should be provided to users. Therefore in this paper, we were calculated link budget of TETRA DMO terminals which were distributing and operating in the country and then predicted reaching distance about radio propagation to be applied with path loss model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2C
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• pp.234-241
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• 2009

TETRA Enhanced Data Service (TEDS), which is an upgrade version of narrow-band ETSI TETRA Release 1 system, can support high speed packet data services in frequency selected fading channel. The performance of M-QAM transceivers employed in the TEDS is significantly affected by the accuracy of channel estimation. In this paper, we consider the design of a decision-directed channel estimation scheme robust to fast fading by estimating the channel by means of a per-survivor processing (PSP) method. The performance of the proposed channel estimation scheme is verified by computer simulation.

• Applied Chemistry for Engineering
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• v.10 no.4
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• pp.608-614
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• 1999

The counter-diffusion of aromatic compounds such as coronene and tetra-phenylporphine by injection of acetone or tetra-phenylporphine solution was studied on aluminas and silica-alumina used widely as catalysts support. The counter-diffusivity was determined from simulation results by using the counter-diffusion model employing ideal adsorbed solution theory. The counter-diffusivities of aromatic compounds in the catalyst supports were ranged in ${\sim}10^{-15}m^2/sec$ in the desorption process by the injection of excess acetone. In the counter-diffusion process with tetra-phenylporphine solution which have similar concentration with adsorption solution, the counter-diffusivities of coronene were also ${\sim}10^{-15}m^2/sec$, and that of tetra-phenylporphine into pores were determined as ${\sim}10^{-11}m^2/sec$. The counter-diffusivities of coronene desobed from the adsorbent were significantly redyced in comparison with the effective diffusivities when there is counter-diffusion flux. The values mainly depended on the existence of counter-diffusion flux, but not concerned with the species and amount of desorbates.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.1209-1212
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• 2007

본 논문에서는 대표적인 산업용 프로토콜인 DNP(Distributed Network Protocol) 3.0과 TETRA(Terrestrial Trunked Radio)의 Gateway System Architecture를 제안한다. TETRA는 재난망 무선통신 기술로써 여러가지 타입의 무선 인터페이스를 제공한다. 이러한 TETRA 기술을 이용해서 원거리에 있는 각 산업용 장비들의 감시 제어를 보다 효율적으로 수행 할 수 있다. 하지만 아직 TETRA의 국내 표준이 이루어지지 않은 상태이기 때문에 본 논문에서는 다양한 산업용 장비와 인터페이스를 할 수 있는 표준을 제공하고자 한다.

• Applied Microscopy
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• v.26 no.3
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• pp.277-291
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• 1996

The structures of the egg envelope in fertilized eggs of three species of characidae, head and tail light fish (Hemigrammus ocellifer), black tetra (Gymnocorymbus ternetzi), and buenos aires tetra (Hemigrammus caudovittatus) were studied using light and electron microscopes. The fertilized eggs in all species were colorless, transparent, spherical and non-floted type. The egg envelopes have a single micropyle resembling the pathway of sperm in the area of the animal pole. The micropyle was surrounded by protruded lines of the egg envelope in a radiated form. Egg envelopes of fertilized eggs in both head and tail light fish and buenos aires tetra consisted of three distinct layers; an outer layer, a middle layer and an inner layer. And that of blacktetra consisted of two layers; an outer layer and an inner layer. Also, an outer layers of both head and tail light fish and black tetra were adhesive types but, in that of buenous aires tetra was non-adhesive type. An outer surface of egg envelope in black tetra was arranged by pores regularly. In that of head and tail light fish and buenos aires tetra have a rough side. An inner layer of egg envelope in fertilized eggs consisted of lamellae alternating with interlamellae of lower electron density; an inner layer of fertilized eggs in head and tail light fish consisted of three layers, that of black tetra was four layers, and that of buenos aires tetra was five layers.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.379-381
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• 2008

TETRA(Terrestrial Trunked Radio) is a digital trunked radio standard developed by the ETSI(European Telecommunications Standards Institute). Currently, TETRA was set Digital TRS in electric power If wireless backbone network. In this time, we use many company's TETRA modem. So, TETRA modem performance evaluation is very important. TETRA modem use two type of Data transfer mode. One is Packet Data using UDP/IP. and the other is SDS(Short Data Service). In this paper, We generate Packet Data using Traffic Generator module. Packet Data transfer 1000 times each 10 bytes to 400 bytes. We analyze transmission delay time, success rate and standard deviation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.10
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• pp.858-864
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• 2012

In South Korea, to effective and systematic response to disasters, the government will build wireless communication network for PPDR(Public Protection and Disaster Relief) on a national level by 2015. To do it, as MOPAS(Ministry of Public Administration and Security) requested the new frequency assignment for PPDR, KCC(Korea Communications Commission) has been examined new frequency allocations about TETRA and WiBro technologies. In this paper, we were defined the technical parameters, were estimated the spectrum of TETRA-TRS requirements for Korean wireless communication of PPDR based on M.2033 methodology recommended by ITU-R.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.4
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• pp.76-85
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• 2008

In this paper, a 800 MHz 1 W cartesian feedback linearized power amplifier is designed and fabricated for TETRA handset application. For amplification of TETRA signal with 200 kHz narrow bandwidth, amplifier linearization performance of more than 30 dBc is improved through the cartesian feedback linearizer at the offset Sequency of ${\pm}25$ kHz. It is clear that the linearization performance is affected by imbalance of gain and phase between I/Q signals and also DC offset. The linearization performance can be maximized by the compensation of those influences. Cartesian feedback is suitable for a liearization technique of narrow band signal with QAM and another modulation signals, as well.