• Journal of Korea Multimedia Society
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• v.20 no.2
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• pp.244-253
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• 2017

Reversible DNA watermarking is capable of continuous DNA storage and forgery prevention, and has the advantage of being able to analyze biological mutation processes by external watermarking by iterative process of concealment and restoration. In this paper, we propose a reversible DNA watermarking method based on histogram multiple shifting of noncoding DNA sequence that can prevent false start codon, maintain original sequence length, maintain high watermark capacity without biologic mutation. The proposed method transforms the non-coding region DNA sequence to the n-th code coefficients and embeds the multiple bits of the n-th code coefficients by the non-recursive histogram multiple shifting method. The multi-bit embedding process prevents the false start codon generation through comparison search between adjacent concealed nucleotide sequences. From the experimental results, it was confirmed that the proposed method has higher watermark capacity of 0.004-0.382 bpn than the conventional method and has higher watermark capacity than the additional data. Also, it was confirmed that false start codon was not generated unlike the conventional method.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.87-94
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• 2008

In this paper, we present a directional error concealment technique to compensate a lost block. Generally, the strong edge of an image has the large amounts of the variance because of its large coefficients in the wavelet domain. For estimating edge direction of a lost block, a $X^2$ hypothesis-testing problem is applied using the variance of wavelet coefficients. The lost block is interpolated according to the estimated edge direction. The pixels for interpolation is obtained from the edge direction. The proposed method outperforms the previous methods in objective and subjective qualities.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06b
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• pp.35-40
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• 1999

이 논문은 디지털 TV의 압축 비트열을 전송할 때, 채널 오류로 인해 디지털 TV 디코더에서 화면을 재생할 때 발생할 수 있는 화질의 저하를 최소화시키는 방법을 기술한다. 텔레비전과 같은 단방향 방송 시스템에서 전송 도중에 오류가 발생하여 수신측에서 전송 오류를 제대로 정정하기 곤란할 때, 재생된 화면이 심각하게 훼손될 수 있다. 이때 오류로 인한 화면의 손상을 주변의 공간적 또는 시간적 상관 정보를 이용하여 화면을 복원하는 동작을 오류 은폐라고 한다. 최근 디지털 TV나 고선명 TV의 기본 부호화 방식으로 많이 사용하고 있는 MPEG 비디오 표준 방식은 공간적인 중복 정보를 압축하기 위해 DCT 변환을 수행하며, 시간적인 중복 정보를 압축하기 위해 움직임 예측과 움직임 보상 방법을 이용한다. 또한 MPEG 비디오 압축 방식은 일종의 차분 부호화 방법을 사용하기 때문에 현재 화면에서 오류가 발생하면 현재 화면뿐만 아니라, 시간적으로 나중에 부호화된 화면에도 오류가 전파된다. 본 논문에서는 MPEG 비트열의 채널 오류의 영향을 분석하여 화면간에 존재하는 시간적인 중복성을 이용하여 움직임 벡터를 추정하여 손상된 부분을 은폐시키는 방법을 제안한다. 기본적으로 손상된 매크로블록의 위와 아래로 인접한 화소값들을 움직임 벡터의 추정에 사용한다. 제안된 방법들 중에서 주변 움직임 벡터들의 가중치를 이용한 평균값 방법과 초기 움직임 벡터를 이용한 확장 영역 움직임 추정 방법이 우수한 결과를 보였다.

• Archives of Plastic Surgery
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• v.34 no.3
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• pp.342-345
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• 2007

Purpose: A common side effect of the scalp reduction is a creation of a 'slot' with the hair growing in the opposite directions away from the scar. Overcoming the unnatural appearance of the slot has been a vexing problem in the scalp reduction surgery. None of the conventional corrective surgical techniques provides a complete and satisfactory aesthetic result. The Frechet flap is a triple transposition flap used for the correction of the slot defect secondary to scalp reduction surgery, seldom needing further scar revision. The Frechet technique provides a solution to the problem of the central slot concealment that is unattainable by other means, such as; Z-plasty and mini-graft. Methods: Authors applied the Frechet technique to Asian patients who had undergone scalp reduction and operated on 4 patients from March, 2000 to January, 2001. Average follow-up period was 13 months. Patients with long scars passing through the temporoparietoccipital zone were excluded. All the undermining was performed in the subgaleal plane, reaching the upper auricular sulcus and stopping just above the nuchal ridge. Results: None of the patients experienced infection, hematoma, nor any permanent hair loss. Transient telogen effluvium at the distal end of flap 2 and 3 was noticeable in one case. Conclusion: In conclusion, the results are aesthetically satisfactory without any significant complications.

• Journal of Korea Multimedia Society
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• v.7 no.7
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• pp.896-904
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• 2004

In this paper, We present an efficient variable rate speech coder for spectral efficiency and packet processing technique for packet loss compensation of a voice codec with 10msec frame in VoIP service. Through disconnecting the users from the spectral resource during silence interval of about 60% period, a variable rate voice coder based on a voice activity detection(VAD) can increase spectral gain by two times. The performance of the method was analyzed by variation of detected voice activity factor and degraded speech frame ratio under various background noise level, and compared those of G.729B of ITU-T 8kbps standard speech codec. A method to compensate lost packets utilized addition of recovery data to a main stream and error concealment scheme for speech quality enhancement, the performance is verified by reconstructed speech quality. The proposed scheme can achieve spectral gain by two times or enhance speech quality by 3dB through reserved bandwidth of VAD. Therefore, the proposed method can enhance a spectral efficiency or speech quality of VoIP.

• Journal of the Korea Society for Simulation
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• v.30 no.3
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• pp.11-17
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• 2021

The 30mm anti-aircraft gun has been developed with various types of weapon systems such as protective, protective complex, and wheel-type anti-aircraft artillery. The role of this anti-aircraft gun is an important anti-aircraft weapon in charge of air defense. Anti-aircraft weapons are tasked with defending the airspace from aircraft attacks. In particular, anti-aircraft weapons are organized in combination with mechanized units. And anti-aircraft weapons are prone to attack by enemies because they operate on the front lines of the battlefield. The enemy is expected to attack our troops by covering up or concealing as much as possible in order to increase their viability. Therefore, this study analyzed whether our 30mm anti-aircraft bullets could subdue the enemy in cover. This study analyzed the performance of 30mm anti-aircraft bullets using the M&S technique. For this study, live shooting and simulation method by M&S were used for the experiment. In this study, steel plate and plywood were used for the live shooting experiment. In addition, in the simulation process through M&S, this study used the PRODAS model, AUTODYN model, and Split-x model to analyze the trajectory, penetration, and fragmentation capability of 30mm anti-aircraft bullets. According to the experimental results, it has been proven that 30mm anti-aircraft bullets can destroy enemy armored vehicles. 30mm anti-aircraft bullets succeeded in quickly subduing enemies concealed in general buildings or forests. In this way, it was possible to minimize damage to allies in advance.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.6
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• pp.100-110
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• 2007

When compressed video data is transmitted over error-prone network such as wireless channel, data is likely to be lost, so the quality of reconstructed picture is severely decreased. It is specially so in case that important information such as motion vector or macroblock mode is lost. H.264/AVC standard includes DP as error resilient technique for protecting important information from error in which data is labeled according to its relative importance. But DP technique requires a network that supports different reliabilities of transmitted data. In general, the benefits of UEP is sought by sending multiple times of same packets corresponding to important information. In this paper, we propose MDC technique based on data partitioning technique. The proposed method encodes motion vector of H.264/AVC standard into multiple parts using MDC and transmits each part as independent packet. Even if partial packet is lost, the proposed scheme can decode the compressed bitstream by using estimated motion vector with partial packets correctly transmitted, so that achieving improved performance of error concealment with minimal effect of channel error. Also in decoding process, the proposed multiple description matching increases the accuracy of estimated lost motion vector and quality of reconstructed video.

• Journal of Korean Academy of Nursing
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• v.25 no.4
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• pp.641-652
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• 1995

Working as nurses, authors found that some patients were not content with their hospital life. Some patients wanted to move to another ward, and others complained about their ward atmosphere. In spite of patients' discomfort, nurses didn't know what made some patients complain about their ward. So, authors tried to find factors that influence atmosphere of hospital wards of the neurosurgery patients. To know the atmosphere of wards, authors selected five neurosurgery ward of a university hospital in Seoul. Observation took a month. An author observed using molar approach, in the morning, in the day time, and in evening time. Authors used concealment /no intervention technique. An author checked condition of people in the wards, and observed their verbal and nonverbal communication behavior their activities and environmental characteristics, and interpreted their meaning through ethnographic research methodology by Spradly. Authors found there was an important factors that influence the atmosphere of ward. It was a human and his attitude. At least one person who was willing to help others made ward atmosphere better. Helping others physically whenever needed, sup-porting the depressed emotionally, offering foods, or talking to others friendly brought good atmosphere. On the contrary, if everyone was indiffernt to others, the atmosphere became cold. Self-centered or selfish behaviors such as occupying too much area, using the toilet too long, covering other's suction bottle without permission and seeing others delicate or urinate were hurtful. In addition to the attitude of patients and their families, unkindness of medical teams including nurses and doctors and tasteless meal caused bad ward atmosphere. Based on this research finding, authors suggest the followings. A For the better atmosphere of ward 1. Nurses should try to make the ward atmosphere better by introducing new patient to older ones. 2. Every ward should have dividing curtains to keep patient's privacy. 3. All hospital personnel should be kind enough to make patients feel that they are repected. 4. Hospital should serve high quality meals to patients. 5. Patients had better stay with those in the similar condition. B. For the future studies 1. Repeated researches are necessary to check reliability of this results. 2. Researches for patients in different area such as ICU, or hemodialysis unit are necessary.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.5
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• pp.1197-1207
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• 2018

PowerShell is command line shell and scripting language, built on the .NET framework, and it has several advantages as an attack tool, including built-in support for Windows, easy code concealment and persistence, and various pen-test frameworks. Accordingly, malwares using PowerShell are increasing rapidly, however, there is a limit to cope with the conventional malware detection technique. In this paper, we propose an improved monitoring method to observe commands executed in the PowerShell and a deep learning based malware classification model that extract features from commands using Convolutional Neural Network(CNN) and send them to Recurrent Neural Network(RNN) according to the order of execution. As a result of testing the proposed model with 5-fold cross validation using 1,916 PowerShell-based malwares collected at malware sharing site and 38,148 benign scripts disclosed by an obfuscation detection study, it shows that the model effectively detects malwares with about 97% True Positive Rate(TPR) and 1% False Positive Rate(FPR).

• The KIPS Transactions:PartA
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• v.17A no.4
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• pp.189-196
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• 2010

This paper presents an improved marker detection algorithm using hybrid features such as corner, line segment, region, and adaptive threshold values, etc. In usual augmented reality environments, there are often marker occlusion and poor illumination. However, existing ARToolkit fails to recognize the marker in these situations, especially, partial concealment of marker by user, large change of illumination and dim circumstances. In order to solve these problems, the adaptive threshold technique is adopted to extract a marker region and a corner extraction method based on line segments is presented against marker occlusions. In addition, a compensating method, corresponding the marker size and center between registered and extracted one, is proposed to increase the template matching efficiency, because the inside marker size of warped images is slightly distorted due to the movement of corner and warping. Therefore, experimental results showed that the proposed algorithm can robustly detect the marker in severe illumination change and occlusion environment and use similar markers because the matching efficiency was increased almost 30%.