• ETRI Journal
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• 제19권3호
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• pp.169-185
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• 1997

This paper presents the design concepts and the system architecture of a mobile exchange for CDMA Mobile System. The paper also discusses complex subsystems in this system and design concepts of these subsystems. To evaluate the performance of the CDMA Mobile System, we have performed a computer simulation based on the framework of the mobile exchange. Simulation results are presented in terms of network traffic load (call attempts per second) and database performance requirements (transactions per second.)

• ETRI Journal
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• 제19권4호
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• pp.389-401
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• 1997

In this paper, we consider the relationship between nonlinearity and correlation immunity of Boolean functions. In particular, we discuss the nonlinearity of correlation immune functions suggested by P. Camion et al. For the analysis of such functions, we present a simple method of generating the same set of functions, which makes it possible to construct correlation immune functions with controllable correlation immunity and nonlinearity. Also, we find a bound for the correlation immunity of functions having maximal nonlinearity.

• ETRI Journal
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• 제24권3호
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• pp.251-254
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• 2002

We developed a method for optimal superframe design in the multi-frequency time division multiple access (MF-TDMA) return-link of a satellite multimedia interactive network called a digital video broadcasting return channel over satellite (DVB-RCS) sub-network. To find the optimal superframe pattern with the maximum data throughput, we formulated the design problem as a non-linear combinatorial optimization problem. We also devised the proposed simple method so that it would have field applicability for improving radio resource utilization in the MF-TDMA return link.

• ETRI Journal
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• 제36권5호
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• pp.847-855
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• 2014

We developed a highly refractive index planarization layer showing a very smooth surface for organic light-emitting diode (OLED) light extraction, and we successfully prepared a highly efficient white OLED device with an embossed nano-structure and highly refractive index planarization layers. White OLEDs act as an internal out-coupling layer. We used a spin-coating method and two types of $TiO_2$ solutions for a planarization of the embossed nano-structure on a glass substrate. The first $TiO_2$ solution was $TiO_2$ sol, which consists of $TiO_2$ colloidal particles in an acidic aqueous solution and several organic additives. The second solution was an organic and inorganic hybrid solution of $TiO_2$. The surface roughness ($R_a$) and refractive index of the $TiO_2$ planarization films on a flat glass were 0.4 nm and 2.0 at 550 nm, respectively. The J-V characteristics of the OLED including the embossed nano-structure and the $TiO_2$ planarization film were almost the same as those of an OLED with a flat glass, and the luminous efficacy of the aforementioned OLED was enhanced by 34% compared to that of an OLED with a flat glass.

• 센서학회지
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• 제22권4호
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• pp.249-255
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• 2013

Gas-sensor array technology, which has been much utilized in the field of food technology by the name of 'electronic nose' is drawing attention in diagnosing lung cancer based on the analysis of the exhaled human breath. Much understanding has been accomplished about the composition of the volatile organic compounds (VOCs) of the human exhaled breath, in spite of some variations depending on research groups due mainly to lack of the standardization of the sensing procedures. Since VOCs may be produced during the process of cellular metabolism, difference in the cellular metabolism between healthy cells and lung cancer cells are expected to be reflected on the composition variation of the exhaled VOCs. Several studies have attempted to apply the gas-sensor array technology to lung cancer analysis using many different types of sensors including metal oxide, carbon black-polymer composite, surface acoustic wave, and gold nanoparticles. In this mini-review VOC as biomarkers, sensor array technology and application of the array technology for the diagnosis of cancer disease have been described.

• 정보와 통신
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• 제25권12호
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• pp.10-18
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• 2008

In this paper, we present a low-power design of H.264 codec based on dedicated hardware and software solution on EMP(ETRI Multi-core platform). The dedicated hardware scheme has reducing computation using motion estimation skip and reducing memory access for motion estimation. The design reduces data transfer load to 66% compared to conventional method. The gate count of H.264 encoder and the performance is about 455k and 43Mhz@30fps with D1(720x480) for H.264 encoder. The software solution is with ASIP(Application Specific Instruction Processor) that it is SIMD(Single Instruction Multiple Data), Dual Issue VLIW(Very Long Instruction Word) core, specified register file for SIMD, internal memory and data memory access for memory controller, 6 step pipeline, and 32 bits bus width. Performance and gate count is 400MHz@30fps with CIF(Common Intermediated format) and about 100k per core for H.264 decoder.

• ETRI Journal
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• 제26권6호
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• pp.661-664
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• 2004

The thermal behavior of an arrayed-waveguide grating made of a silica/polymer hybrid waveguide was examined. We experimentally confirmed that the hybrid waveguide is effective to decrease the temperature and polarization dependence of the center wavelength owing to the negative thermo-optic coefficient of the refractive index and extremely low baking temperature of the polymer cladding. However, the detachment of the polymer cladding from the silica core, which took place either during a repeated heat cycle test or during long-term storage in atmosphere, was a serious problem for practical use.

• ETRI Journal
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• 제27권5호
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• pp.497-503
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• 2005

In this paper, we present a performance analysis for an MPEG-4 video codec based on the on-chip network communication architecture. The existing on-chip buses of system-on-a-chip (SoC) have some limitation on data traffic bandwidth since a large number of silicon IPs share the bus. An on-chip network is introduced to solve the problem of on-chip buses, in which the concept of a computer network is applied to the communication architecture of SoC. We compared the performance of the MPEG-4 video codec based on the on-chip network and Advanced Micro-controller Bus Architecture (AMBA) on-chip bus. Experimental results show that the performance of the MPEG-4 video codec based on the on-chip network is improved over 50% compared to the design based on a multi-layer AMBA bus.

• ETRI Journal
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• 제34권6호
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• pp.970-973
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• 2012

In this letter, we report on the development progress of a pressure control organic vapor deposition (PCOVD) technology used to design and build a large area deposition system. We also investigate the growth characteristics of a pentacene thin film by PCOVD. Using the PCOVD method, the mobility and on/off current ratio of an organic thin-film transistor (OTFT) on a plastic substrate are $0.1cm^2/Vs$ and $10^6$, respectively. The developed OTFT can be applied to a flexible display on a plastic substrate.

• ETRI Journal
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• 제34권6호
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• pp.946-949
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• 2012

We present the optimization of a birefringence-enhanced-waveguide (BWG)-based polarization beam splitter (PBS) in a Mach-Zehnder interferometer (MZI) configuration and analyze the structure-dependent or polarization-dependent phase difference, using a delay-line MZI (DL-MZI). We fabricate the DL-MZI using silica-based planar lightwave circuit technology and, using the DL-MZI, demonstrate the ability to optimize a PBS by measuring the birefringence of the BWG and structure-dependent phase offset.