• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 통신소사이어티 추계학술대회논문집
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• pp.265-268
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• 2003

In this paper, we propose new simple and efficient stopping criteria for W-CDMA turbo decoding. The new criteria are based on the sum of logarithm of absolute extrinsic information values and the count of one-estimations calculated after each component decoder. The calculation of the proposed criteria can be made simpler by summing one of ten values without any penalty. This Proposed method can be implemented with negligible overhead and no extra memory. Simulation results on W-CDMA standard shows that the number of iterations required is reduced compared to the existing stopping criteria without degrading the BER performance. Reduced iterations and simple operations make the proposed criteria desirable for low-power turbo decoder.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.1002-1005
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• 1995

This paper presents an enhanced preprocessing and recognition algorithm for automatic vehicle license plate recognition system. The algorithm first applies horizontal gradient filter followed by thresholding and mathematical morphology operation for preprocessing. The final stage of the preprocessing is the application of connected component analysis in order to estimate the license plate region. For the recognition of the serial numbers of the plates, we developed a very effective algorithm. We call this zerocrossing count algorithm. This paper presents a detail of this algorithm and compare the performance with a template matching algorithm which utilizes correlation coefficient.

• 한국정보전자통신기술학회논문지
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• 제11권5호
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• pp.475-480
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• 2018

In OFDM-based systems, FFT is a critical component since it occupies large area and consumes more power. In this paper, we present a low hardware-cost and low power 512-point pipelined FFT design method for OFDM applications. To reduce the number of twiddle factors and to choose simple design architecture, the radix-$2^4-2^3$ algorithm are exploited. For twiddle factor multiplication, we propose a new canonical signed digit (CSD) complex multiplier design method to minimize the hardware-cost. In hardware implementation with Intel FPGA, the proposed FFT design achieves more than about 28% reduction in gate count and 18% reduction in power consumption compared to the previous approaches.

• 한국산업융합학회 논문집
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• 제22권2호
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• pp.191-199
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• 2019

In this paper, dissimilar friction welding were produced using 15 mm diameter solid bar in chrome molybedenum steel(SCM440) to stainless steel(STS316L) to investigate their mechanical properties. Consequently, optimal welding conditions were n=2000 rpm, HP=70 MPa, UP=140 MPa, HT=10 sec and UT=10 sec when the metal loss(Mo) is 8.6 mm. In addition, an acoustic emission technique was applied to evaluate the optimal friction welding condition. AE parameters including the cumulative count, amplitude and energy showed a various changes according to the friction condition. A continuous type waveforms and low frequency spectrum was presented in friction time. On the other hand, a burst type waveform and high frequency spectrum was exhibited in pressing time.

• Journal of Power Electronics
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• 제19권3호
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• pp.676-690
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• 2019

This paper presents a switched capacitor (SC) based bidirectional dc-dc converter topology for high voltage gain applications. The proposed converter is able to operate with multiple integral voltage conversion ratios based on user input. The architecture of a user-friendly, inductor-less multi-voltage-gain bidirectional dc-dc converter is proposed in this study. The inductor-less or magnetic-less design of the proposed converter makes it effective in higher temperature applications. Furthermore, the proposed converter has a reduced component count and lower voltage stress across its switches and capacitors when compared to existing SC converters. An output impedance analysis of the proposed converter is presented and compared with popular existing SC converters. The proposed converter is simulated in the OrCAD PSpice environment and the obtained results are presented. A 200 W hardware prototype of the proposed SC converter has been developed. Experimental results are presented to validate the efficacy of the proposed converter.

• Communications for Statistical Applications and Methods
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• 제31권3호
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• pp.263-277
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• 2024

This paper proposes new parameterizations of the tilted beta binomial distribution, obtained from the combination of the binomial distribution and the tilted beta distribution, where the beta component of the mixture is parameterized as a function of their mean and variance. These new parameterized distributions include as particular cases the beta rectangular binomial and the beta binomial distributions. After that, we propose new linear regression models to deal with overdispersed binomial datasets. These new models are defined from the proposed new parameterization of the tilted beta binomial distribution, and assume regression structures for the mean and variance parameters. These new linear regression models are fitted by applying Bayesian methods and using the OpenBUGS software. The proposed regression models are fitted to a school absenteeism dataset and to the seeds germination rate according to the type seed and root.

• Advances in pediatric surgery
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• 제17권2호
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• pp.179-187
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• 2011

Experimental tracheal ligation (TL) has been shown to reverse the pulmonary hypoplasia associated with congenital diaphragmatic hernia (CDH) and to normalize gas exchange. The purpose of this study was to determine whether the TL would correct the surfactant deficiency present in the fetal rabbit model of CDH by using lamellar body count. Lamellar bodies are synthesized and secreted by the type II pneumocytes of fetal lung. The phospholipids present in these bodies constitute the major component of pulmonary surfactant. Twenty-one pregnant New Zealand rabbits underwent hysterotomy and fetal surgery on gestational day 24. Two fetuses of each pregnant rabbit were operated. In the fetus of one end of bicornuate uterus, left DH was created by excision of fetal diaphragm through open thoracotomy (DH Group). In the fetus of the other end of bicornuate uterus, left DH and TL were created (TL Group). The fetuses were delivered by Cesarean section on gestational day 31. Fourteen in control group, 12 in the DH group and 13 in TL group were born alive. En bloc excision of lungs, bronchi and trachea was done in all newborn rabbits. A five Fr catheter was inserted through trachea and repeated irrigations with 10 cc normal saline were done. The irrigated fluid was centrifuged at $280{\times}g$ for 5 minutes and the lamellar bodies were counted with the upper level fluid in platelet channel of electronic cell counter. The average lamellar body counts were $37.1{\pm}14.2{\times}10^3/{\mu}L$ in control group, $11.5{\pm}4.4 {\times}10^3/{\mu}L$ in DH group, and $6.5{\pm}0.9{\times}10^3/{\mu}L$ in TL group. Lamellar body count in DH group was lower than in control group and did not increase after TL. This study shows TL has no therapeutic effect on decreased surfactant level of CDH and the pregnant rabbit is appropriate for the animal model of CDH.

• 한국해양공학회지
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• 제25권6호
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• pp.91-96
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• 2011

In this paper, friction welded joints were constructed to investigate the mechanical properties of welded 15-mm diameter solid bars of Mg alloy (AZ31B). The main friction welding parameters were selected to endure reliable quality welds on the basis of visual examination, tensile tests, impact energy test, Vickers hardness surveys of the bonds in the area and heat affected zone (HAZ), and macrostructure investigations. The study reached the following conclusions. The tensile strength of the friction welded materials (271 MPa) was increased to about 100% of the AZ31B base metal (274 MPa) under the condition of a heating time of 1 s. The metal loss increased lineally with an increase in the heating time. The following optimal friction welding conditions were determined: rotating speed (n) = 2000 rpm, heating pressure (HP) = 35 MPa, upsetting pressure (UP) = 70 MPa, heating time (HT) = 1 s, and upsetting time (UT) = 5 s, for a metal loss (Mo) of 10.2 mm. The hardness distribution of the base metal (BM) showed HV55. All of the BM parts showed levels of hardness that were approximately similar to friction welded materials. The weld interface of the friction welded parts was strongly mixed, which showed a well-combined structure of macro-particles without particle growth or any defects. In addition, an acoustic emission (AE) technique was applied to derive the optimum condition for friction welding the Mg alloy nondestructively. The AE count and energy parameters were useful for evaluating the relationship between the tensile strength and AE parameters based on the friction welding conditions.

• Toxicological Research
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• 제32권4호
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• pp.317-325
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• 2016

Increased access to highly active antiretroviral therapy (HAART) has made the management of drug toxicities an increasingly crucial component of HIV. This study investigated the effects of adjuvant use of coconut oil and HAART on testicular morphology and seminal parameters in Sprague-Dawley rats. Twelve adult male Sprague-Dawley rats, weighing 153~169 g were distributed into four groups (A-D) and treated as follows: A served as control (distilled water); B (HAART cocktail-Zidovudine, Lamivudine and Nevirapine); C (HAART + Virgin coconut oil 10 mL/kg) and D (Virgin coconut oil 10 mL/kg). After 56 days of treatment, animals were killed and laparotomy to exercise the epididymis for seminal fluid analyses done whilst testicular tissues were processed for histo-morphometric studies. Result showed a significant decline in sperm motility (P < 0.05) and count (P < 0.0001) in HAART-treated animals while there was insignificant changes in other parameters in groups C and D except count that was reduced (P < 0.0001) when compared with controls. Histomorphological studies showed HAART caused disorders in seminiferous tubular architecture with significant (P < 0.01) decline in epithelial height closely mirrored by extensive reticulin framework and positive PAS cells. Adjuvant Virgin coconut oil + HAART resulted in significant decrease in seminiferous tubular diameter (P < 0.05), but other morphometric and histological parameters were similar to control or Virgin coconut oil alone (which showed normal histoarchitecture levels). While derangements in testicular and seminal fluid parameters occurred following HAART, adjuvant treatment with Virgin coconut oil restored the distortions emanating thereof.

• 한국통신학회논문지
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• 제34권7B호
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• pp.677-685
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• 2009

무선 센서네트워크에서 에너지 절약을 위해 필요한 송선전력을 제어하는 기법들이 많이 연구 되었다. 그러나 기존 연구들은 송신전력제어 과정에서 최적화된 송신전력 단계를 계산하기 위해 많은 패킷이 필요하다. 본 논문에서는 추가척인 제어 패킷을 발생시키지 않고 최단경로를 고려하는 송신전력제어 기법을 제안한다. 그 기법은 네트워크 구성에 필요한 광고 메시지를 최대한 활용하여 제어 패킷을 사용하지 않으며 네트워크 구성 초기에 최대 송선전력 단계로 광고 메시지를 전달하여 구성된 최단경로를 기준으로 한다. 제안한 기법의 평가를 위해 TinyOS 에서 제안한 기법을 적용하였다. 그리고 21개의 노드를 이용하여 네트워크를 구성하고 형균 전류 소요량, 평균 네트워크 깊이 등을 측정하였다. 측정한 결과 제안한 기법을 척용한 네트워크가 이전보다 송신 시 명균 전류량이 약 24.7% 만큼 적으며 네트워크의 흡 수가 일반 네트워크 홉 수보다 약 41% 적였다.