• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4475-4481
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• 2014

A histogram equalization method have been used traditionally for the image enhancement of low quality images. This uses the transformation function, which is a cumulative density function of an input image, and it has mathematically maximum entropy. This method, however, may yield whitening artifacts. This paper proposes the weighted histogram equalization method based on histogram equalization. It has Weber-Fechner's law for a human's vision characteristics, and a dynamic range modification to solve the problem of some methods, which yield a transformation function, regardless of the input image. Finally, the proposed transformation function was calculated using the weighted average of Weber-Fechner and the histogram equalization transformation functions in a modified dynamic range. The simulation results showed that the proposed algorithm effectively enhances the contrast in terms of the subjective quality. In addition, the proposed method has similar or higher entropy than the other conventional approaches.

• Journal of Digital Convergence
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• v.13 no.6
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• pp.157-164
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• 2015

An efficient retrieval of useful information is a prerequisite of an optimal decision making system. Hence, A research of data mining techniques finding useful patterns from the various forms of data has been progressed with the increase of the application of Big Data for convergence and integration with other industries. Each technique is more likely to have its drawback so that the generalization of retrieving useful information is weak. Another integrated technique is essential for retrieving useful information. In this paper, a uncertainty measure of information is calculated such that algebraic probability is measured by Bayesian theory and then information entropy of the probability is measured. The proposed measure generates the effective reduct set (i.e., reduced set of necessary attributes) and formulating the core of the attribute set. Hence, the optimal decision rules are induced. Through simulation deciding contact lenses, the proposed approach is compared with the equivalence and value-reduct theories. As the result, the proposed is more general than the previous theories in useful decision-making.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1B
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• pp.21-27
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• 2012

The HLLL scheme, proposed by T. Linde, determines all the wave speeds from the initial states because the middle wave is evaluated by the introduction of a generalized entropy function. The scheme is considered a genuine successor to the original HLL scheme because it is completely separated form the Roe's linearization scheme unlike the HLLE scheme and does not rely on the exact solution unlike the HLLC scheme. In this study, a numerical model was configured by the HLLL scheme with the total energy as a generalized entropy function to solve governing equations, which are the one-dimensional shallow water equations without source terms and with an additional conserved variable relating a concentration. Despite the limitations of the first order solutions, results to three cases with the exact solutions were generally accurate. The HLLL scheme appeared to be superior in comparison with the other HLL-type schemes. In particular, the scheme gave fairly accurate results in capturing the front of wetting and drying. However, it revealed shortcomings of more time-consuming calculations compared to the other schemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.307-315
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• 2017

Random number generator(RNG) is essential in cryptographic applications. As recently a system using small devices such as IoT, Sensor Network, SmartHome appears, the lightweight cryptography suitable for this system is being developed. However due to resource limitations and difficulties in collecting the entropy, RNG designed for the desktop computer are hardly applicable to lightweight environment. In this paper, we propose a lightweight RNG to produce cryptographically strong random number using sensors. Our design uses a Hankel matrix, block cipher as the structure and sensors values as noise source. Futhermore, we implement the lightweight RNG in Arduino that is one of the most popular lightweight devices and estimate the entropy values of sensors and random number to demonstrate the effectiveness and the security of our design.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.4
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• pp.327-334
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• 2006

The aerial photos need in a simple object such as cartography and ground cover classification and also in a social objects such as the city plan, environment, disaster, transportation etc. However, the shadow, which includes when taking the aerial photos, makes a trouble to interpret the ground information, and also users, who need the photos in their field tasks, have a restriction. Generally the shadow occurs by the building and surface topography, and the detail cause is by changing of the illumination in an area. For removing the shadow this study uses the single image and processes the image without the source of image and taking situation. Also, applying the entropy minimization method it generates the 1-D gray-scale invariant image for creating the shadow edge mask and using the Canny edge detection creates the shadow edge mask, and finally by filtering in Fourier frequency domain creates the intrinsic image which recovers the 3-D color information and removes the shadow.

• Analytical Science and Technology
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• v.11 no.6
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• pp.440-447
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• 1998

Polydentate Schiff base ligands 5-Br-BSDT(bis(5-bromosalicylaldehyde)diethylenetriamine) having $N_3O_2$ atoms, 5-Br-BSTT(bis(5-bromosalicylaldehyde)triethylenetetramine) having $N_3O_2$ atoms, 5-Br-BSTP(bis(5-bromosalicylaldehyde)tetraethylenepentamine) having $N_3O_2$ atoms were synthesized. Stability constants of the complexes between these ligands and the metal ions such as Cu(II), Ni(II) and Zn(II) were measured in DMSO by a polarographic method. It was observed that all metal(II) ions employed in this study formed 1 : 1 complexes with Schiff base ligands. Stability constants for the ligands were in the order of Cu(II)>Ni(II)>Zn(II), and for complex formation were in the order of 5-Br-BSTP>5-Br-BSTT>5-Br-BSDT according to the increasing in the number of donor atoms. Both enthalpy and entropy changes are obtained in negative valves. Exothermicity for the complex formation indicated tight binding between the ligands and metal ions. The negative entropy change would be related to the fact that solvent molecules are strongly interacting with the metal complexes.

• Korean Journal of Food Science and Technology
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• v.16 no.1
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• pp.41-46
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• 1984

The pectic enzymes produced from Aspergillus niger were separated into three fractions (F-A, F-I and F-II) by means of Sephadex and DEAF-Sephadex column chromatography. Each enzyme fraction was characterized by determining viscosity change and reducing surgar of the pectic acid-enzyme mixture and analyzing thin layer chromatogram of the reaction products. F-I rapidly reduced the viscosity of pectic acid solution and released reducing groups in a random manner so that appeared to be an endo-polygalacturonase (endo-PG). The optimum pH of endo-PG for viscosity reducing activity was 4.2 and that for releasing reducing surgar was 4.7. In the thermal inactivation of endo-PG of $30-45^{\circ}C$, the enthalpy of activation was 217.3 kj/mole and z-value was $7.5^{\circ}C$. F-II and F-A were determined as endo-polymethylgalacturonase and exo-polygalacturonase, respectively.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.29 no.4
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• pp.48-54
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• 2000

자성재료에 자기장을 걸어주변 가열되고 자기장을 제거하면 냉각되는 성질이 있는데, 이를 자기열량효과(magnetocaloric effect)라고 하며, 이것을 이용해서 저온을 생성시키는 방법을 자기냉동(magnetic refrigeration)이라고 한다. 큐리 온도(Curie temperature) 부근의 강자성체에 자 기장이 가해지면 전자례도내에서 쌍을 이루지 않은 전자들의 자기모벤트들이 자기장에 평행 하게 배열되는데, 이로 인해 열역학적 무질서의 척도인 엔트로피는 낮아지고 이러한 손실을 보상하기 위해 재료의 온도가 올라가게 된다.반대로 자기장이 제거되면 자기모벤트가 본래의 무질서한 상태로 돌아오며, 엔트로피가 증가하 고 재료의 온도는 떨어지게 되는 것이다. 역사적으로 보면 1881년에 Warburg가 큐리온도 부근의 철에서 자기열량효과를 처음 발견하였으며. 1926년과 1927년에 Debye와 Giauque가 각각 단열소자볍 (adiabatic demagnetization)을 제안함으로써 실용화되기 시작하여 주로 극저온을 얻는 방법으로 이용되어 왔다. 1950년도 이전의 연구는 절대온도 영도(OK)에 도달하고 자 하는 순수과학적인 노력으로서 개방사이클(open cycle)을 이용한 단열냉각 방식을 추구하 였으나, 1950년 이후부터는 공학적인 응용을 목적으로 밀폐사이클(closed cycle)을 형성하는 자기냉동기에 관한 연구가 진행되었다. 1976년에 Brown은 희토류(rare earth) 금속인 가돌리늄(Gd)을 사용하여 유체(물 80%와 에틸 알코올 20%)를 재생시킴으로써 상온에서 작동 하는 자기냉동기를 보고한 바 있다. 그는 7 T의 큰 자장을 이용하였으며, 고온부와 저온부의 온도는 각각 $46^{\circ}C와\;-1^{\circ}C로서\;47^{\circ}C$의 온도간격을 얻었다. 자기냉동에 있어서의 또 하나의 중요한 진전은 1978년과 1982년에 Steyert와 Barclay에 의해서 능동자기재생기(active magnetic r regenerator)의 개념이 소개되고 개발된 것으로, 이는 자성재료가 냉매로서 뿐만 아니라 열전달 유체의 재생기로도 사용되는 방식이다. 이상과 같은 자기냉동기술의 발달에 이어서 1997년에 미국의 Astronautics사(Wisconsin주 Madison시 소재)와 Ames 연구소(Iowa주 Ames 시 소재)의 공동연구팀이 발표한 두 가지의 새로운 진전으로 인해 공기조화 및 냉동분야에 적용할 수 있는 자기냉동기의 실용화 가능성이 한층 높아졌다. 이들의 연구결과는 (1) 자기냉동이 실온에서도 실현 가능한 기술이며 증기압 축식 냉동에 필적할 만하다는 것을 보인 것과 (2) 이미 알려져 있던 자기냉동재료보다 자기 열량효과가 훨씬 큰 새로운 재료를 발견한 것이다. 이로써 자기냉동에 대한 관심과 기대가 한결 커지고 있다. 본 원고에서는 자기냉동의 원리가 되는 자기열량효과와 이를 이용한 자기냉동의 방법 그리고 최근에 이루어진 새로운 진전에 대해 소개하고 공기조화 및 냉동분야에의 적용 가능성을 전망해 보고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.2
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• pp.268-275
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• 2020

A lightweight hardware design of self-timed ring based true random number generator (TRNG) suitable for information security applications is described. To reduce hardware complexity of TRNG, an entropy extractor with feedback structure was proposed, which minimizes the number of ring stages. The number of ring stages of the FSTR-TRNG was determined to be a multiple of eleven, taking into account operating clock frequency and entropy extraction circuit, and the ratio of tokens to bubbles was determined to operate in evenly-spaced mode. The hardware operation of FSTR-TRNG was verified by FPGA implementation. A set of statistical randomness tests defined by NIST 800-22 were performed by extracting 20 million bits of binary sequences generated by FSTR-TRNG, and all of the fifteen test items were found to meet the criteria. The FSTR-TRNG occupied 46 slices of Spartan-6 FPGA device, and it was implemented with about 2,500 gate equivalents (GEs) when synthesized in 180 nm CMOS standard cell library.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.89-94
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• 2007

High duality BiSrCaCuO thin films fabricated by using the i-beam sputtering method at various substrate temperatures, $T_{sub}$ and oxidation gas pressures, $pO_3$. The correlation diagrams of the BiSrCaCuO phases with Tsub and $pO_3$ are established in the 2212 and 2223 compositional films. In spite of 2212 compositional sputtering, Bi2201 and Bi2223 as well as Bi2212 phases come out as stable phases depending on $T_{sub}$ and $pO_3$. From these results, the thermodynamic evaluation of ${\Delta}H$ and${\Delta}S$, which are related with Gibbs' free energy change for single Bi2212 or Bi2223 phase, was performed.