• The KIPS Transactions:PartC
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• v.18C no.6
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• pp.445-450
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• 2011

In the vehicular ad hoc network environment, the clustering mechanism is one of the efficient mechanisms to deliver broadcast messages. Most clustering mechanisms require message exchanges between vehicles to build stable clusters, which causes overhead. In order to reduce this overhead, CF-IVC [1] proposes the mechanism to construct clusters based on the vehicle speed. However, since CF-IVC does not consider the road traffic condition and the driver's behavior, it may result in inefficient clusters. Therefore, in this paper, we propose a mechanism to establish efficient clusters based on the vehicle local information with considering the road maximum speed limit and the road traffic condition. The performance of the proposed mechanism is validated by comparing with those of the simple flooding and CF-IVC through NS-2 simulations.

• Journal of Broadcast Engineering
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• v.19 no.2
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• pp.250-256
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• 2014

Non-reference P frame coding is used to enhance coding efficiency in low-delay encoding configuration of Internet Video Coding (IVC), which is being standardized as a royalty-free video codec in MPEG. The existing method of non-reference P frame coding which was adopted in the reference Test Model of IVC (ITM) 4.0 adaptively applies a non-reference P frame with a fixed coding structure based on the magnitude of motion vectors (MVs), however, which unexpectedly degrades the coding efficiency for some sequences. In this paper, the existing non-reference P frame coding is improved by changing non-reference P frame coding structure and applying a new adaptive method using the ratio of the amount of generated bits of non-reference frames to that of reference frames as well as MVs. Experimental results show that the proposed non-reference P frame coding gives 6.6% BD-rate bit saving in average over ITM 7.0.

• Journal of Chest Surgery
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• v.42 no.2
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• pp.275-278
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• 2009

Leiomyosarcoma of the inferior vena cava (IVC) is a rare malignant tumor. Yet tumors of a smooth muscle origin are the most common primary neoplasms of the major veins, and the inferior vena cava is the most common site of origin. We report here on a 65-year-old female patient who had been suffering from dyspnea and abdominal discomfort for 3 weeks before admission. The abdominal computed tomography (CT) scan and IVC cavogram showed an IVC mass extending from the right atrium to above the level of the right renal vein, obstructing the IVC, and the radiological findings were suggestive of an IVC leiomyosarcoma. We resected the tumor and reconstructed the IVC with a patch PTFE graft. The follow-up abdominal CT revealed no recurrence and obstruction of the IVC for 6 months after the operation.

• The Korean Journal of Pain
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• v.34 no.4
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• pp.471-478
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• 2021

Background: The effect of lumbar spinal stenosis (LSS) and peripheral vascular disease (PVD), which occurs with similar degenerative conditions, when seen together, has not been studied. The aim of this study is to examine and compare the relationship between pain, balance, disability, fear of falling, and kinesiophobia in LSS patients with intermittent vascular claudication (IVC). Methods: Seventy-two patients diagnosed with LSS using magnetic resonance imaging participated in this study. Thirty-five patients with IVC symptoms and showing vascular lesions by lower extremity venous and arterial Doppler ultrasonography imaging were included in the IVC-LSS group. The pain, static balance, dynamic balance, disability, fear of falling, and kinesiophobia were evaluated using the numeric rating scale, single leg stance test, Time Up and Go (TUG), the Oswestry Disability Index (ODI), Fall Efficacy Scale-International (FES-I), and Tampa Scale for Kinesiophobia (TSK), respectively. Results: Age and female sex were found to be higher in the IVC-LSS group (P = 0.024; P = 0.012). The IVC-LSS group had a shorter single leg stance time and TUG test duration, pain intensity, ODI, FES-I, and TSK scores were higher than patients with LSS (P = 0.001). Pain, fear of falling, and kinesiophobia were moderately correlated with disability in the IVC-LSS group. No relationship was found between pain and dynamic balance. Also, the pain was not related to kinesiophobia. Conclusions: The findings indicated that IVC causes loss of balance and an increase in pain, disability, fear of falling, and kinesophobia in patients with LSS.

• Journal of Broadcast Engineering
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• v.25 no.6
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• pp.1013-1016
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• 2020

This paper presents a selective encryption and decryption method exploiting the start code of the IVC bitstream. The existing encryption methods for video are largely classified into two methods: Naive Encryption Algorithm (NEA) and Selective Encryption Algorithm (SEA). Since NEA encrypts the entire bitstream, it has the advantage of high security but has the disadvantage of high computational complexity. SEA improves the encryption and decryption speed compared to NEA by encrypting a part of the bitstream, but there is a problem that security is relatively low. The proposed method improves the encryption and decryption speed and the security of the existing SEA by using the start code of the IVC bitstream. As a result of the experiment, the proposed method reduces the encryption speed by 96% and the decryption speed by 98% on average compared to the NEA.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.469-472
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• 2007

최근 많은 광대역 유무선 통신 응용분야에서 OFDM(Orthogonal Frequency Division Multiplexing) 방식을 표준기술로 채택하고 있다 OFDM 방식의 고속 무선 데이터 통신를 위한 FFT 프로세서는 일반적으로 DSP(Digital Signal Processing)로 구현되었으나, 큰 전력 소비를 필요로 한다. OFDM의 단점인 전력문제를 보안하기 위해서 Current-mode FFT LSI가 제안되었다. 본 논문에서는 Current-mode FFT LSI의 구현을 위한 저전력 IVC를 설계하였다. 설계된 IVC는 FFT Block의 출력이 $13.65{\mu}A$ 이상일 때에 3V 이상의 전압을 출력하고, FFT Block의 출력이 $0.15{\mu}A$ 이하일 때에 0.5V 이하의 전압을 출력한다. 그리고 IVC의 총 소모전력은 약 1.65mW이다. $0.35{\mu}A$ 공정에서의 저전력 IVC를 설계함으로서, $0.35{\mu}A$ 공정에서의 Current-mode FFT LSI의 설계가 가능해졌다. 저전력 OFDM 통신용 Current-mode FFT LSI는 무선통신의 발전에 기여할 것으로 전망한다.

• Journal of Chest Surgery
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• v.28 no.3
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• pp.268-273
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• 1995

Budd- chiari syndrome resulting from a membranous obstruction of the inferior vena cava[IVC is a rare congenital anomaly. From January 1989 to December 1993, 8 cases of IVC obstruction was treated in Kyung Hee Univ. Hospital. There were 2 male and 6 female patients between 34 and 66 years of age[mean 47.3$\pm$11.9 years of age . 4 patients were treated with angioplasty by balloon catheter and 4 patients were treated with operative correction using cardiopulmonary bypass, profound hypothermia and total circulatory arrest. These 4 patients were repaired the constricted IVC with autologous pericardial patch. In surgically treated patients, all of the specimens were confirmed to be membranous web histopathologically. Postoperative outcome in operative correcting patients was uneventful and postoperative angiography showed unobstructed flow through the IVC with filling of the hepatic veins.The above 8 patients were followed up from 10 months to 56 months [ mean 36.43 17.24 months and recurrent IVC obstruction or stenosis was not seen.

• Tuberculosis and Respiratory Diseases
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• v.42 no.5
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• pp.787-792
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• 1995

The obstruction of inferior vena cava(IVC) is uncommon condition. The classification is based on the obstructive sites of major anatomic segments of IVC. The main collateral pathways of interruption of IVC were central channels through ascending lumbar veins, intervertebral veins and azygos-hemiazygos complex. However, the complete obstruction of mid-portion of IVC, accompanying collateral cirulation with pericardiacophrenic vein was rarely reported. We had experienced a case of complete obstruction of mid-portion of IVC with lobulated left cardiac border, which was unforgettable characteristic finding on chest radiograph. It was confirmed by venographic examination that the lobulated left cardiac shadow was a collateral circulation of pericardiacophrenic vein.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.4
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• pp.569-574
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• 2007

최근 많은 광대역 유무선 통신 응용분야에서 OFDM(Orthogonal Frequency Division Multiplexing) 방식을 표준기술로 채택하고 있다. OFDM 방식의 고속 무선 데이터 통신을 위한 FFT 프로세서는 일반적으로 DSP(Digital Signal Processing)로 구현되었으나, 큰 전력 소비를 필요로 한다. 따라서, OFDM 통신방식의 단점인 전력문제를 보완하기 위해서 전류모드 FFT LSI가 제안되었고, 저소비전력 전류모드 FFT LSI를 동작시키기 위해서는 전류모드를 전압모드로 바꾸는 VIC(Voltage to Current Converter) 그리고 다시 전류모드를 전압모드로 바꾸어 주는 IVC(Current to Voltage Converter)가 필요하다. 그러나, OP-AMP로 구현되는 종래의 IVC는 회로규모가 크고, 전력소비가 크며, LSI 내에 크고 정확한 높은 저항을 필요로 한다. 또한 전류모드신호처리에서 많이 이용되는 Current Mirror 회로 등의 출력단자로부터 전류신호를 입력받은 경우, 입력단자간의 전위차가 발생하며, DC offset 전류가 발생하는 등의 문제점을 갖는다. 따라서 본 연구에서는 저전력 동작이 가능하고, 향후, single chip 응용이 가능한 IVC를 $0.35{\mu}m$ 공정에서 설계함으로서, $0.35{\mu}m$ 공정에서의 전류모드 FFT LSI의 전압모드 출력이 가능해졌다 설계된 IVC는 FFT LSI의 출력이 디지털신호로 환산한 ${\pm}1$인 점을 감안하여, 전류모드 FFT LSI의 출력이 $13.65{\mu}A$ 이상일 때에 3.0V의 전압을 출력하고, FFT LSI의 출력이 $0.15{\mu}A$ 이하일 때에 0.5V 이하의 전압을 출력하도록 하였으며, IVC의 총 소비전력은 약 1.65mV이하로 평가되었다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.5
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• pp.908-916
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• 2000

This study was undertaken to purify the anticoagulant polysaccharide from Pachymeniopsis elliptica. The anticoagulant compound (PE-2IVc-2-1) was isolated from the crude polysaccharide (PE-2) by the sequential steps such as ultrafiltration (PE-2IV), anion-exchange chromatography of DEAE-Toyopearl 650C(PE-2IVc), size-exclusion chromatography of Sepharose CL-6B (PE-2IVc), and HPLC Shodex OHpak column chromatography (PE-2IVc-2-1). The apparent molecular weight of purified polysaccharide (PE-2IVc-2-1) was approximately 710 kDa. It was mainly composed of galactose (48.6%) and 3,6-anhydrogalactose (44.0%) with 27.1% of sulfate residue, in addition a trace amount of xylose (3.6%), glucose (1.1%), mannose (1.1%), arabinose (0.8%) and fucose (0.8%). The IR spectrum of the polysaccharide showed the characteristic bands of S=O(1116.74 and 1143.17 $cm^{-1}$) and C-O-S (828.19 $cm^{-1}$) stretching, respectively. The anticoagulant effect of PE-2 in ex vivo was proportional to the concentration of intravenously injected dose, up to 100 mg/kg.