• Journal of Korea Multimedia Society
• /
• v.16 no.7
• /
• pp.841-851
• /
• 2013

The infectious information hiding system(IIHS) is proposed for secure distribution of high quality video contents by applying optimized watermark embedding and detection algorithms to video codecs. And the watermark as infectious information is transmitted while target video is displayed or edited by codecs. This paper proposes a fast and effective reversible watermarking and infectious information generation for IIHS. Our reversible watermarking scheme enables video decoder to control video quality and watermark strength actively for by adding control code and expiration date with the watermark. Also, we designed our scheme with low computational complexity to satisfy it's real-time processing in a video codec, and to prevent time or frame delay during watermark detection and video restoration, we embedded one watermark and one side information within a macro-block. Experimental results verify that our scheme satisfy real-time watermark embedding and detection and watermark error is 0% after reversible watermark detection. Finally, we conform that the quality of restored video contens is almost same with compressed video without watermarking algorithm.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.20 no.5
• /
• pp.445-450
• /
• 2000

The integrity of the turbine rotors can be assessed by measuring reversible permeability and Vickers hardness of the aged rotors at service temperature. The measurement system of reversible permeability, which measured by applied alternating perturbing magnetic field, was constructed in order to evaluate material degradation, nondestructively. The test specimen was 1Cr-1Mo-0.25V steel used widely for turbine rotor material, and the specimens were prepared by the isothermal heat treatment at $630\;^{\circ}C$. The reversible permeability of the test materials were measured at room temperature. The peak interval of reversible permeability and Vickers hardness decreased with the increase of degradation. The degradation of test material may be determined nondestructively by the lineality of Vickers hardness and the peak interval of reversible permeability.

• Journal of Korea Water Resources Association
• /
• v.39 no.3 s.164
• /
• pp.253-259
• /
• 2006

In almost all previous hydrological studies, the standard approach adopted for nonlinear time series analysis is to perform system characterization first followed by forecasting. However, a practical inverse approach for forecasting nonlinear hydrological time series was proposed recently To investigate the applicability standard approach method and inverse approach, this study used a theoretical time series (Mackey-Glass time series) and daily streamflows of the Bear River in Idaho. To predict a theoretical time series and daily streamflow, this study used local approximation method. From chaos analysis, chaotic characteristics are found in daily streamflow of the Bear River in Idaho. Resulting from 1, 3 and 5-day prediction, inverse approach method is shown to be better than the standard approach for a theoretical chaotic time series and daily streamflow.

• Journal of the Korean Society of Radiology
• /
• v.82 no.1
• /
• pp.261-266
• /
• 2021

Ischemic stroke is one of the manifestations of reversible cerebral vasoconstriction syndrome (RCVS). Many precipitants and associated disorders of RCVS have been suggested. However, few case reports have indicated an association between anemia and RCVS. Here, we report a case of a 66-year-old female with severe iron deficiency anemia (IDA), who presented with ischemic stroke and cerebral vasoconstriction, which gradually improved with conservative treatment. High-resolution vessel wall magnetic resonance imaging findings and reversibility suggested the possibility of RCVS. In patients with RCVS and ischemic stroke, IDA should be considered. Prompt management should be delivered to prevent disease progression and recurrence.

• Tuberculosis and Respiratory Diseases
• /
• v.48 no.4
• /
• pp.522-529
• /
• 2000

Backgrounds : Assessment of the presence and degree of reversibility of airflow obstruction is clinically important in patients with asthma or chronic obstructive pulmonary disease. The measurement of peak expiratory flow(PEF) is a simple, fast, and cheap method to assess the severity of obstruction and its degree of reversibility. Assessing the reversibility of airflow obstruction by peak expiratory flow(PEF) measurements is practicable in general practice, but its usefulness has not been well investigated. We compared PEF and $FEV_1$ in assessing reversibility of airflow obstruction in patients with chronic obstructive pulmonary disease or asthma and developed a practical criterion for assessing the presence of reversibility in general practice. Methods : PEF measurements were performed (Spirometry) in 80 patients(aged 24-78) with a history of asthma or chronic obstructive lung disease before and after the inhalation of 200 g salbutamol. The change in PEF was compared with the change in forced expiratory volume in one second($FEV_1$). Reversible airflow obstruction was analyzed according to American Thoracic Society(ATS) criteria. Results : A 12% increase above the prebronchodilator value and a 200ml increase in either FVC or $FEV_1$ reversibility were observed in 45%(36) of the patients. Relative operating characteristic(ROC) analysis showed that an absolute improvement in PEF of 30 l/min gave optimal discrimination between patients with reversible and irreversible airflow obstruction(the sensitivity and specificity of an increase of 30 l/min in detecting a 12% increase above the prebronchodilator value and a 200ml increase in either FVC or $FEV_1$ were 72.2% and 72.7% respectively, with a positive predictive value of 68.4%). Conclusions : Absolute changes in PEF can be used to diagnose reversible airflow obstruction.

• KIPS Transactions on Software and Data Engineering
• /
• v.4 no.5
• /
• pp.231-240
• /
• 2015

Medical imagery require to protect the privacy with preserving the quality of the original contents. Therefore, reversible watermarking is a solution for this purpose. Previous researches have focused on general imagery and achieved high capacity and high quality. However, they raise a distortion over entire image and hence are not applicable to medical imagery which require to preserve the quality of the objects. In this paper, we propose a novel reversible watermarking for medical imagery, which preserve the quality of the objects and achieves high capacity. First, object and background region is segmented and then predicted error histogram-based reversible watermarking is applied for each region. For the efficient watermark embedding with small distortion in the object region, the embedding level at object region is set as low while the embedding level at background region is set as high. In experiments, the proposed algorithm is compared with the previous predicted error histogram-based algorithm in aspects of embedding capacity and perceptual quality. Results support that the proposed algorithm performs well over the previous algorithm.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.38 no.3
• /
• pp.316-324
• /
• 2001

A table compression method for reversible variable length code is proposed in this paper. TNWT(Transition Number and Weight of Tree) method, which uses the transition number of bits within a symbol and the level of a code tree, is proposed. Compression of table values is performed after arrangment of values that is not distinghishable by transition number and weights. In decoding, the transition number and weight of code are used. In this method, the table for RVLC decoding can be implemented with a smaller memory.

• Journal of Korean Philosophical Society
• /
• v.105
• /
• pp.193-214
• /
• 2008

This paper is about to analyse Merleau-Ponty's notion of flesh on textual evidences through the structure of perception and to apply this result to his theory of the others. In the first place, we study what he thinks of philosophical investigation and thus of the essence of philosophy. With this process, we find out that perception is more important than reflection in philosophical investigation. Differently from the objective or objectivistic viewpoint, the truth of perception is revealed to go beyond distinction between consciousness and object. This truth refers to reversibility which Merleau-Ponty thinks to be the ultimate truth. The reversibility of perception leads to chiasms which reveal and unreveal the beings. In the final analysis, the flesh as reversibility is the Being in the beings. When it comes to the problem of other minds, we are confirmed through the movement of flesh that self-presence is the presence to the differentiated world, namely the others.

• Prospectives of Industrial Chemistry
• /
• v.24 no.6
• /
• pp.3-18
• /
• 2021

가역적인 표면 젖음성의 제어가 가능한 스마트 표면은 첨단 센서, 기능성 멤브레인 등 여러 산업분야에 적용될 수 있는 계면제어 기술로써 많은 관심을 받을 것으로 기대된다. 표면의 젖음성은 표면의 화학적 구조와 기하학적 입체 구조에 의해 영향을 받는 데, 특히 외부자극에 의해 소재 물성을 가변시킬 수 있는 스마트 고분자 소재를 나노구조가 제어된 표면에 도입함으로써 표면의 젖음성을 초발수에서 초친수로 가역적으로 전환시킬 수 있는 스마트 표면을 효과적으로 구현할 수 있다. 자극 응답성 스마트 소재는 인가하는 외부자극에 따라 물리적 자극(빛, 온도, 전기, 자기)과 화학적 자극(pH, 용매, 이온)으로 구분할 수 있으며, 이를 복합적으로 적용한 이중/다중 유발 자극에 반응하는 소재가 있다. 본 기고문에서는 외부자극에 응답하는 자극응답성 고분자를 나노 구조 표면에 도입하여 초발수에서 초친수로의 가역적인 젖음성 변화가 가능한 고기능성 스마트 표면의 최근 연구 동향과 미래 전망에 대해 소개하고자 한다. 이런 다양한 외부자극을 이용한 표면 특성의 가역적 제어 기술을 통해 물-오일의 분리, 바이오센서, 약물 전달, 소프트로보틱스와 같은 스마트 소재의 잠재적 발전 가능성 또한 엿볼 수 있을 것으로 기대된다.

• The KIPS Transactions:PartB
• /
• v.18B no.1
• /
• pp.1-10
• /
• 2011

Reversible watermarking inserts watermark into digital media in such a way that visual transparency is preserved, which enables the restoration of the original media from the watermarked one without any loss of media quality. It has various applications, where high capacity and high visual quality are major requirements. This paper presents a new effective multi-round embedding scheme for the differential histogram-based reversible watermarking that satisfies high capacity requirements of the application. The proposed technique exploits the row-column cross scanning to fully utilize the locality of images when multi-round embedding phase to the message inserted image. Through experiments using multiple kinds of test images, we prove that the presented algorithm provides 100% reversibility, effectiveness of multi-round embedding, and higher visual quality, while maintaining the induced-distortion low.