• Journal of Sensor Science and Technology
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• v.32 no.4
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• pp.223-231
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• 2023

An integrated-optical biochemical sensor structure that can perform homogeneous and surface sensing using a 2×2 balanced-bridge Mach-Zehnder interference structure based on the optimized SOI slot optical waveguide was described, and its performance and characteristics were evaluated. Equations for the two output optical powers were derived and examined using the transfer matrices of a 3-dB coupler and phase shifter (channel waveguide). The length of the 3-dB coupler was determined such that the two output optical powers were same using these formulas. In homogeneous sensing, the effect of the refractive index of an analyte in the range of 1.33-1.36 on the two output optical power distributions was numerically derived, and the sensitivity was calculated based on each output and the difference between the two outputs, the former and the latter being 7.5796-19.0305 [au/RIU] and 15.2601-38.1351 [au/RIU], respectively. In the case of surface sensing, the sensitivity range of the refractive index of 1.337 based on each of the two outputs was calculated as -2.2490--3.5854 [au/RIU] and 1.2194-3.8012 [au/RIU], and the sensitivity range of 4.8048-7.0694 [au/RIU] was confirmed based on the difference between the two outputs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1A
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• pp.80-86
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• 2010

This work has been measured and analyzed the device degradation of NBTI (Negative Bias Temperature Instability) stress induced the increase of gate-induced-drain-leakage(GIDL) current for p-MOS transistors of gate channel length 0.13 [${\mu}m$]. From the relation between the variation of threshold voltage and subthreshold slop by NBTI stress, it has been found that the dominant mechanism for device degradation is the interface state generation. From the GIDL measurement results, we confined that the EHP generation in interface state due to NBTI stress led to the increase of GIDL current. As a results, one should take care of the increased GIDL current after NBTI stress in the ultra-thin gate oxide device. Also, the simultaneous consideration of reliability characteristics and dc device performance is highly necessary in the stress parameters of nanoscale CMOS communication circuit design.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.3
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• pp.165-171
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• 2023

The rotary joint connecting the upper and lower structures of construction machinery and special vehicles transmits hydraulic pressure as the shaft and housing rotate, and multiple seals are assembled to prevent oil leakage into the oil flow channel. Because the seal material is rigid and difficult to assemble, we sought a method to assemble it after cutting. The shapes of the cutting surface are L-shaped and / shaped, and the leakage standard when hydraulic pressure is applied is the contact pressure generated on the cutting surface. The structure and material of the seal are composed of a double elastomer, and nonlinear contact structural analysis is performed when only the high-rigidity PE material is cut. Studies have shown that the shorter the cutting length, the better the leakage prevention and the higher the possibility of leakage to the bottom surface where NBR and PE come into contact rather than the top surface where the PE and the housing come into contact.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7A
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• pp.964-972
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• 1999

In this paper, we proposed a simulation model to which apply the AAL 2 (AAL type 2) between BSC and MSC in the cellular mobile communication systems. We suggested the frame structure of processing the packets of short length and the scheme which multiplex to one or more ATM cell. Also, we analyzed the performance of the APR, transmission delay, and channel transmission efficiency used in the packetized voice traffic and the low bit-rate data traffic such as fax. From the simulation results, the maximum number of users are 47 users without using AAL 2 multiplexing, but the maximum number of users are 70 (Non-Overlapping scheme) users, 110 (Overlapping scheme) users, respectively. Thus, we knew that the Overlapping scheme is more efficient than the Non-Overlapping scheme. Finally, we showed that the optimum transmission buffer size is 4 ATM cells in the cellular communication systems with the bandwidth of 2 Mbps.

• Progress in Medical Physics
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• v.13 no.2
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• pp.85-89
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• 2002

We authors developed a new small-size birdcage RF coil for animal MR images. And we compared signal-to-noise ratio (SNR) of the new small coil with a conventional knee coil. The dimension of the low-pass type birdcage coil with 12 elements at 37 MRI system are 13 cm outer diameter, 12 cm inner diameter and 20 cm length. For each element, the width of copper tape is 0.05 mm, thickness is 8 mm and length is 20 cm. The small birdcage coil with 12 elements exhibited 7 resonance modes. The isolation of the quadrature channel could be achieved more than 20 ㏈. The coil quality factor (Q value) was 98.6. The SNR of the animal coil was 243.2 on the average and was about twice as high as the conventional knee coil. The present study successfully demonstrated that the small birdcage coil could provide high quality animal MR images with the improved SNR. Therefore, it is expected that the small birdcage coil could be used in the clinical diagnosis and research studies for veterinary medicine in the near future.

• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.78-84
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• 2008

Recent earthquakes near nuclear power plants in Korea have triggered public concerns about possible seismicity of the Ulsan Fault Zone in the south-eastern part of the Korean peninsula. To reveal subsurface structures of this fault zone, we conducted high-resolution seismic refraction and reflection surveys, and closely spaced gravity measurements in the Dongchon River valley north of Ulsan, Korea. Here alluvium covers the north-south trending fault zone in a 1-km wide valley. Both source points and receivers were spaced at 5-m intervals for the 24-channel seismic refraction and reflection methods, along two profiles of 835 m and 415 m length. Gravity data were also measured along these profiles at 131 stations using a 10-m interval. Synergetic interpretation of seismic refraction, high-resolution seismic reflection, and gravity surveys across the valley indicates that the Ulsan Fault Zone was formed by apparent north-south strike-slip motions during the Cretaceous, and that some faults may have been reactivated by east-west compressional or transpressional stresses during the Tertiary or Quaternary.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.11
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• pp.637-644
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• 2014

This paper investigates the detection performance of fault location using STDR(sequence time domain reflectometry) and SSTDR(spread spectrum time domain reflectometry) with various length and types of sequences, and then, proposes an improved detection technique by eliminating the injected signal in SSTDR. The detection error rates are compared and analyzed in power line channel model with various fault locations, fault types, and spreading sequences such as m-sequence, binary Barker sequence, and 4-phase Frank sequence. It is shown that the proposed technique is able to improve the detection performance obviously when the reflected signal is weak or the fault location is extremely close.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.5 no.1
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• pp.22-30
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• 1994

The error probability of the DS-CDMA / DPSK cellular mobile communication system with CCI canceller and MRC diversity reception technique has been analyzed in the cellular radio channel which is characterized by AWGN, Multi-User Interference(MUI) and m-distribution fading. System capacity i. e., number of user per cell has been derived and the evaluated results are shown in figures as a function of PN code sequence length, fading index, BER, number of diversity branches and $E_b/N_o$, Here, the voice activity factor is assumed to be 3/8, the number of sectors in a cell 3 and Multi-User Iner- ference is modeled as Gaussian process.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.11
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• pp.3-8
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• 2012

Two-dimensional product code has been studied for correcting burst errors on the storage systems. An RS-LDPC product code consists of an RS code in horizontal direction and an LDPC code in vertical direction. First, we detect the position of burst errors by using RS code, then LDPC code corrects the errors by using the burst error positions. In storage system, long burst errors are occurred by various reason. So, we need a strong code for correcting the long burst errors. RS-LDPC product code is good for long burst errors. However, as the storage density grows the length of the burst errors will be longer. Thus, we propose an LDPC-LDPC product code, it is strong for correcting the very long burst errors. Also, the proposed LDPC-LDPC product code performs better than RS-LDPC product code when the random errors are occurred, because a row direction LDPC code performs better than row direction RS code.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4A
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• pp.336-344
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• 2005

Discrete Wavelet Transform(DWT) is the oncoming generation of compression technique that has been selected for MPEG4 and JEPG2000, because it has no blocking effects and efficiently determines frequency property of temporary time. In this paper, we propose an efficient bit-serial architecture for the low-power and low-complexity DWT filter, employing two-channel QMF(Qudracture Mirror Filter) PR(Perfect Reconstruction) lattice filter. The filter consists of four lattices(filter length=8) and we determine the quantization bit for the coefficients by the fixed-length PSNR(peak-signal-to-noise ratio) analysis and propose the architecture of the bit-serial multiplier with the fixed coefficient. The CSD encoding for the coefficients is adopted to minimize the number of non-zero bits, thus reduces the hardware complexity. The proposed folded 1D DWT architecture processes the other resolution levels during idle periods by decimations and its efficient scheduling is proposed. The proposed architecture requires only flip-flops and full-adders. The proposed architecture has been designed and verified by VerilogHDL and synthesized by Synopsys Design Compiler with a Hynix 0.35$\mu$m STD cell library. The maximum operating frequency is 200MHz and the throughput is 175Mbps with 16 clock latencies.