• ETRI Journal
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• 제43권1호
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• pp.109-119
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• 2021

Self-recovery is a tamper-detection and image recovery methods based on data hiding. It generates two types of data and embeds them into the original image: authentication data for tamper detection and reference data for image recovery. In this paper, a region-based scalable self-recovery (RSS) method is proposed for salient-object images. As the images consist of two main regions, the region of interest (ROI) and the region of non-interest (RONI), the proposed method is aimed at achieving higher reconstruction quality for the ROI. Moreover, tamper tolerability is improved by using scalable recovery. In the RSS method, separate reference data are generated for the ROI and RONI. Initially, two compressed bitstreams at different rates are generated using the embedded zero-block coding source encoder. Subsequently, each bitstream is divided into several parts, which are protected through various redundancy rates, using the Reed-Solomon channel encoder. The proposed method is tested on 10 000 salient-object images from the MSRA database. The results show that the RSS method, compared to related methods, improves reconstruction quality and tamper tolerability by approximately 30% and 15%, respectively.

• Journal of the Korean Statistical Society
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• 제19권1호
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• pp.88-92
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• 1990

In the problem of the recovery of interblock information in balanced incomplete block designs(BIBD), it is well known that a truncated estimator dominates the untruncated estimator under mean squared error loss. This paper shows that the domination result holds universally for every nondecreasing loss function.

• The Korean Journal of Pain
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• 제27권3호
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• pp.210-218
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• 2014

Brachial plexus injury is a potential complication of a brachial plexus block or vessel puncture. It results from direct needle trauma, neurotoxicity of injection agents and hematoma formation. The neurological presentation may range from minor transient pain to severe sensory disturbance or motor loss with poor recovery. The management includes conservative treatment and surgical exploration. Especially if a hematoma forms, it should be removed promptly. Comprehensive knowledge of anatomy and adept skills are crucial to avoid nerve injuries. Whenever possible, the patient should not be heavily sedated and should be encouraged to immediately inform the doctor of any experience of numbness/paresthesia during the nerve block or vessel puncture.

• Journal of Yeungnam Medical Science
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• 제35권1호
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• pp.104-108
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• 2018

Syncope is defined as a transient loss of consciousness and postural tone, characterized by rapid onset, short duration, and spontaneous recovery. Stellate ganglion block (SGB) is a nerve block method that is used for treatment of neuropathic pain in the head, neck and upper extremities, especially trigeminal neuralgia, postherpetic neuralgia and complex regional pain syndrome. SGB can modulate and stabilize the sympathetic nervous system, which prevents it from overexcitation and improves symptoms of syncope. The authors report a patient who was treated for pain and edema of both upper extremities with SGB, then showed improvement in recurrent syncope followed by chest pain and overall quality of life.

• 한국컴퓨터정보학회논문지
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• 제23권1호
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• pp.57-66
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• 2018

It is known that a single-key and a related-key attacks on AES-128 are possible for at most 7 and 8 rounds, respectively. The security of CMAC, a typical block-cipher-based MAC algorithm, has very high possibility of inheriting the security of the underlying block cipher. Since the attacks on the underlying block cipher can be applied directly to the first block of CMAC, the current security margin is not sufficient compared to what the designers of AES claimed. In this paper, we consider HMAC-DM-AES-128 as an alternative to CMAC-AES-128 and analyze its security for reduced rounds of AES-128. For 2-round AES-128, HMAC-DM-AES-128 requires the precomputation phase time complexity of $2^{97}$ AES, the online phase time complexity of $2^{98.68}$ AES and the data complexity of $2^{98}$ blocks. Our work is meaningful in the point that it is the first security analysis of MAC based on hash modes of AES.

• The Korean Journal of Pain
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• 제9권1호
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• pp.260-263
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• 1996

High spinal block is a rare complication during epidural block, but it may result in serious events. 56-year-old man with gall stones was scheduled for cholecystectomy under general anesthesia. After operation, lumbar epidural catheterization was done at $T_{8-9}$ interspace for postoperative pain control. At the recovery room, initial bolus drug (0.1% bupivacaine 10 ml containing fentanyl $100{\mu}g$) was administered via epidural catheter and observed carefully. 15 minutes later, hypotension and bradycardia ouccurred. Hartman' solution was administered rapidly and ephedrine 5 mg was injected. 30 minutes after drug administration, loss of consciousness and respiratory arrest developed. Tracheal intubation was done immediately. Cardiovascular and respiratory functions were monitored continuously. The location of intrathecal catheter was confirmed by cerebrospinal fluid (CSF) seen in syringe after aspiration of catheter. The patient recovered gradually and was placed in the ward 4 hours after drug administration, without any problems. He was discharged 1 week later in good health.

• The Korean Journal of Pain
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• 제19권2호
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• pp.164-167
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• 2006

Background: There have been an increasing number of reports about infection-related complications after epidural block, and the analysis of these previous reports may offer valuable information for the prevention and treatment of such complications. Methods: We searched for complications about infection that was related to epidural blockade procedures by using the Medline Search program. We analyzed the types of infection-related complications as well as the potential risk factors, the time course from symptom development to treatment, the causative organisms and the treatment outcomes. Results: Seventeen cases were identified. The types of complications were epidural abscess, subdural abscess, spinal arachnoiditis, bacterial meningitis and aseptic meningitis. Five patients received a single block and twelve patients received a continuous block with catheterization. The most common site of epidural catheterization was the lumbar area and eight patients had indwelling catheters for less than fifteen days. Eight patients had a diabetes mellitus as a risk factor and fourteen patients showed less than seven days from the development of symptoms to treatment. Eleven patients received laminectomy and intravenous antibiotics as a treatment and eight patients had full recovery without neurological deficit. Conclusions: Early diagnosis and treatment is essential for the favorable outcome of infection-related complication after epidural block. In addition, absolute sterile technique should always be performed and patient education concerning these potential complications must be accompanied.

• Journal of Microbiology and Biotechnology
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• 제19권10호
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• pp.1230-1237
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• 2009

The selective plugging strategy of Microbial Enhanced Oil Recovery (MEOR) involves the use of microbes that grow and produce exopolymeric substances, which block the high permeability zones of an oil reservoir, thus allowing the water to flow through the low permeability zones leading to increase in oil recovery. Bacillus licheniformis TT33, a hot water spring isolate, is facultatively anaerobic, halotolerant, and thermotolerant. It produces EPS as well as biosurfactant and has a biofilm-forming ability. The viscosity of its cell-free supernatant is $120\;mPa{\cdot}s$ at $28^{\circ}C$. Its purified EPS contained 26% carbohydrate and 3% protein. Its biosurfactant reduced the surface tension of water from 72 to 34 mN/m. This strain gave $27.7{\pm}3.5%$ oil recovery in a sand pack column. Environmental scanning electron microscopy analysis showed bacterial growth and biofilm formation in the sand pack. Biochemical tests and Amplified Ribosomal DNA Restriction Analysis confirmed that the oil recovery obtained in the sand pack column was due to Bacillus licheniformis TT33.

• 대한전자공학회논문지SP
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• 제42권5호
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• pp.95-102
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• 2005

본 논문은 잡음이 존재하는 전송 선로를 통한 영상 전송 시 발생하는 손실 블록에 대한 방향성 복구 방법을 제안한다. 손실된 블록은 웨이블릿 부대역의 에너지(EWS)와 DC값의 차이(DDC)에 의해 적응적으로 선택되어진 이웃 블록들을 이용한 선형 보간법에 의해 복구된다. 고정된 4-이웃 블록을 사용하여 복구하는 방법은 강한 에지영역에서 블록화된 블러링 효과를 발생시킨다. 본 논문의 방향성 복구 방법은 에지나 영상 내의 방향성 정보에 따라 적응적으로 변하는 이웃 블록을 사용하기 때문에 강한 에지영역에서 효과적이다. EWS만 이용하여 이웃블록을 선택하는 경우는 수직, 수평 에지에서는 좋은 성능을 보이지만 대각 에지에 대해서는 약점을 가지고 있다. DDC만을 이용하여 이웃블록을 선택하는 경우는 대각 에지에서는 좋은 성능을 보이지만 에지 프로파일에 따라 약점을 보인다. 따라서 EWS와 DDC 정보를 함께 이용하여 적응적으로 손실 블록을 복구할 이웃블록을 선택함으로써 두 가지방법의 약점을 서로 보완하여 더 좋은 성능을 보일 수 있다. 모의실험 결과 본 논문의 블록 복구 방법은 객관적 평가와 주관적 평가에서 모두 좋은 성능을 보였다.

• 방송공학회논문지
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• 제4권1호
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• pp.76-85
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• 1999

프랙탈 부호화 방식에서의 블록 손실 효과는 DCT 기반 블록 부호화 방식에서와는 달리 손실 블록의 참조에 의한 에러 전파 효과 때문에 보다 심각한 화질 저하를 초래한다. 따라서 본 논문에서는 Jacquin 방법에 의해 프랙탈 부호화된 영상을 ATM 망과 같은 손실망을 통해 전송할 경우 발생할 수 있는 블록 손실을 복구하는 방법을 제안한다. Jacquin 의 프랙탈 부호화 체계는 중요도에 따라 머리부호와 본체 부호의 2계층 부호화 체계로 구성된다. 제안된 블록 손실 복구 알고리듬의 핵심 기법은 블록 특성이 손실 블록과 유사한 인접 치역 블록들의 축소 사상 파라미터들을 사용하여 손실 화소들을 추정하는 츠랙탈 외삽이며, 이는 복호화 과정에서 반복적으로 손실 블록들에 적용된다. 실험을 통하여, 제안된 복구 알고리듬이 주관적 화질 뿐만 아니라 PSNR 에서도 우수한 성능을 갖고 있음을 보인다.