• Title/Summary/Keyword: resynchronization

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An adaptive keystream resynchronization algorithm by using address field of LAPB (LAPB의 주소 영역을 이용한 적응 난수열 재동기 알고리즘)

  • 윤장홍;이주형;황찬식;양상운
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.10
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    • pp.2181-2190
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    • 1997
  • The synchronous stream cipher has the problem of synchronization loss by cycle slip. Synchronization loss make the state which sender and receiver can't communicate and it may make the receiving system disordered. To lessen the risk, we usually use a continuous resynchronization which achieve resynchronization at fixed timesteps by inserting synchronization pattern and session key. While we can get effectively resynchronizationby continuous resynchronization, there are some problems. In this paper, we proposed an adaptive resynchronization algorithm for cipher system using LAPB protocol. It is able to solve the problem of the continunous resynchronization.The proposed adaptive algorithm make resynchronization only in the case that the resynchronization is occurred by analyzing the address field of LAPB. It measure the receiving rate of the address field in the decesion duration. If the receiving rate is smaller than threshold value, it make resynchronization or not. By using adaptively resynchronization, it solves the problems of continunous resynchronization. When the proposed adaptive algorithm is applied to the synchronous stream cipher system which is used in X.25 packet network, it reduced the time for resynchronization by ten times. It means that 11.3% of total data for transmit is compressed.

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An adaptive resynchronization technique for stream cipher system in HDLC protocol (HDLC 프로토콜에서 운용되는 동기식 스트림 암호 통신에 적합한 적응 난수열 재동기 기법)

  • 윤장홍;황찬식
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.9
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    • pp.1916-1932
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    • 1997
  • The synchronous stream cipher which require absoulte clock synchronization has the problem of synchronization loss by cycle slip. Synchronization loss makes the state which sender and receiver can't communicate with each other and it may break the receiving system. To lessen the risk, we usually use a continuous resynchronization method which achieve resynchronization at fixed timesteps by inserting synchronization pattern and session key. While we can get resynchronization effectively by continuous resynchroniation, there are some problems. In this paper, we proposed an adaptive resynchronization algorithm for cipher system using HDLC protocol. It is able to solve the problem of the continuous resynchronization. The proposed adaptive algorithm make resynchronization only in the case that the resynchronization is occurred by analyzing the address field of HDLC. It measures the receiving rate of theaddress field in the decision duration. Because it make resynchronization only when the receiving rate is greateer than the threshold value, it is able to solve the problems of continuous resynchronization method. When the proposed adaptive algorithm is applied to the synchronous stream cipher system in packet netork, it has addvance the result in R_e and D_e.

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Cardiac Resynchronization Therapy Defibrillator Treatment in a Child with Heart Failure and Ventricular Arrhythmia

  • Kim, Hak Ju;Cho, Sungkyu;Kim, Woong-Han
    • Journal of Chest Surgery
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    • v.49 no.4
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    • pp.292-294
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    • 2016
  • Cardiac resynchronization therapy (CRT) is a new treatment for refractory heart failure. However, most patients with heart failure treated with CRT are adults, middle-aged or older with idiopathic or ischemic dilated cardiomyopathy. We treated a 12-year-old boy, who was transferred after cardiac arrest, with dilated cardiomyopathy, left bundle-branch block, and ventricular tachycardia. We performed cardiac resynchronization therapy with a defibrillator (CRT-D). After CRT-D, left ventricular ejection fraction improved from 22% to 4 4% assessed by echocardiogram 1 year postoperatively. On electrocardiogram, QRS duration was shortened from 206 to 144 ms. The patient's clinical symptoms also improved. For pediatric patients with refractory heart failure and ventricular arrhythmia, CRT-D could be indicated as an effective therapeutic option.

Cardiac Resynchronization Therapy (심장재동시화치료)

  • Kim, Hyong-Jun;Shin, Dong-Gu
    • Journal of Yeungnam Medical Science
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    • v.22 no.2
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    • pp.131-140
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    • 2005
  • Heart failure is a clinical syndrome comprised of a number of symptoms and signs associated with congestion and/or hypoperfusion. Specific pharmacologic therapies have been developed to slow disease progression from early to more advanced stages. Once symptoms have developed, aggressive multimodality interventions are instituted to alleviate symptoms and improve clinical status and quality of life; especially in those patients that present symptoms. Recently, an evolving adjunctive therapeutic modality, that involves using implanted electrical devices: cardiac resynchronization with or without implantable cardioverter defibrillators (ICD). has been used for management. Cardiac resynchronization therapy (CRT) is a proven treatment for selected patients with heart failure-induced conduction disturbances and ventricular dyssynchrony. When used in combination with stable, optimal medical therapy, CRT is designed to reduce symptoms and improve cardiac function by restoring the mechanical sequence of ventricular activation and contraction. This review summarizes the rationale, procedure, clinical trials, and clinical indications for CRT.

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A Fast Parity Resynchronization Scheme for Small and Mid-sized RAIDs (중소형 레이드를 위한 빠른 패리티 재동기화 기법)

  • Baek, Sung Hoon;Park, Ki-Wong
    • KIPS Transactions on Computer and Communication Systems
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    • v.2 no.10
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    • pp.413-420
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    • 2013
  • Redundant arrays of independent disks (RAID) without a power-fail-safe component in small and mid-sized business suffers from intolerably long resynchronization time after a unclean power-failure. Data blocks and a parity block in a stripe must be updated in a consistent manner, however a data block may be updated but the corresponding parity block may not be updated when a power goes off. Such a partially modified stripe must be updated with a correct parity block. However, it is difficult to find which stripe is partially updated (inconsistent). The widely-used traditional parity resynchronization manner is a intolerably long process that scans the entire volume to find and fix inconsistent stripes. This paper presents a fast resynchronization scheme with a negligible overhead for small and mid-sized RAIDs. The proposed scheme is integrated into a software RAID driver in a Linux system. According to the performance evaluation, the proposed scheme shortens the resynchronization process from 200 minutes to 5 seconds with 2% overhead for normal I/Os.

Resynchronization of Modified JPEG Using a Power Allocation Scheme in a Direct Sequence CDMA System

  • Yim, Choon-Sik;Roh, Jae-Sung;Choi, Eun-Suk;Baek, Joong-Hwan;Cho, Sung-Joon
    • ETRI Journal
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    • v.24 no.5
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    • pp.405-408
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    • 2002
  • In this paper, we discuss recovery schemes for errors occurring when image data encoded with variable length coding (VLC) is transmitted through additive white Gaussian noise (AWGN) and multiple-access interference in direct sequence code division multiple access (DS/CDMA) systems. VLC such as JPEG is so sensitive to channel errors that severe degradation in decoded images occurs even if only one or two bits have errors. This is due to the loss of synchronization at the image decoder. We propose a resynchronization scheme using a power allocation method in wireless DS/CDMA transmission. Through simulation, we know that the proposed method has a more robust resynchronization capability and higher objective and subjective quality than the conventional method.

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Effect of resynchronization programs according to the ovarian status on pregnancy outcomes in dairy cows

  • Jaekwan Jeong;Uihyung Kim;Illhwa Kim
    • Korean Journal of Veterinary Research
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    • v.63 no.2
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    • pp.14.1-14.4
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    • 2023
  • This study evaluated the effect of resynchronization programs on pregnancies in dairy cows. Of 1,342 cows confirmed not pregnant after their first artificial insemination (AI), those with a corpus luteum (CL) were resynchronized using Ovsynch or PG-GnRH-Ovsynch and those without a CL were resynchronized using GnRH-Ovsynch or modified Double-Ovsynch. There were no differences (p > 0.05) in the pregnancies per AI either between the Ovsynch (31.3%) and PG-GnRH-Ovsynch (34.0%) or between the GnRH-Ovsynch (38.7%) and modified Double-Ovsynch (39.5%). In conclusion, Ovsynch and GnRH-Ovsynch programs could be preferred to resynchronize cows with and without a CL, respectively, from the perspective of reducing costs and labor.

Random Sequence Synchronization for Radio Secure Communication Using Synchronous Stream Cipher (동기식 스트림 암호와 방식을 이용한 무선 암호 통신에서의 난수열 동기)

  • 손해성;홍진근김강욱황찬식
    • Proceedings of the IEEK Conference
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    • 1998.06a
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    • pp.66-69
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    • 1998
  • The synchronous stream cipher has the advantage that one bit error in the ciphertext only affects the corresponding bit in the plaintext, but it requires the perfect synchronization between encryptor and decryptor. For synchronization, a periodic resynchronization has been used in many applications. In this paper, we propose the periodic resynchronization scheme for radio secure communication and evaluate the performances according to the period of sync pattern and session key under radio channel environment having 10-2~ 10-6 BER.

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Cardiac Resynchronization Therapy Using a Dual Chamber Pacemaker in Patients with Severe Left Ventricular Dysfunction and a Left Bundle Branch Block

  • Jung, Jae Jun;Kim, In Sook;Jeong, Jae-Han;Lee, Young Tak;Jeong, Dong Seop
    • Journal of Chest Surgery
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    • v.46 no.4
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    • pp.289-292
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    • 2013
  • Through the use of a dual chamber (DDD) pacemaker, we achieved a cardiac resynchronization effect in a 51-year-old female patient who was transferred to our hospital from another hospital for an operation for three-vessel coronary artery disease. Her electrocardiogram showed a left bundle branch block (LBBB) and a prolonged QRS interval of 166 milliseconds. Severe left ventricle (LV) dysfunction was diagnosed via echocardiography. Coronary artery bypass grafting (CABG) was then performed. In order to accelerate left atrial activation and reduce the conduction defect, DDD pacing using right atrial and left and right ventricular pacing wires was initiated postoperatively. The cardiac output was measured immediately, and one and twelve hours after arrival in the intensive care unit. The cardiac output changed from 2.8, 2.4, and 3.6 L/min without pacing to 3.5, 3.4, and 3.5 L/min on initiation of pacing. The biventricular synchronization using DDD pacing was turned off 18 hours after surgery. She was transferred to a general ward with a cardiac output of 3.9 L/min. In patients with coronary artery disease, severe LV dysfunction, and LBBB, cardiac resynchronization therapy can be achieved through DDD pacing after CABG.

Cardiac Resynchronization Therapy in Infant with Dilated Cardiomyopathy during Extracorporeal Membrane Oxygenator

  • Bang, Ji Hyun;Oh, You Na;Ko, Jae-Kon;Kang, So Yeon;Baek, Jae Suk;Park, Chun Soo
    • Journal of Chest Surgery
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    • v.48 no.1
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    • pp.55-58
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    • 2015
  • Although heart transplantation is a final therapeutic option in pediatric patients with dilated cardiomyopathy (DCMP), the shortage of pediatric heart donors is a major obstacle. In adults with DCMP characterized by cardiac dyssynchrony, cardiac resynchronization therapy (CRT) is known to be an effective treatment option. However, there is a lack of evidence on the effectiveness of CRT in infants with DCMP. Several studies have reported improvement in hemodynamics and cardiac performance following CRT in infants with DCMP. Here, we report CRT in an infant with DCMP during extracorporeal membrane oxygenation with 5 months of follow-up.