• 광학세계
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• 통권150호
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• pp.31-41
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• 2014

현재까지 많은 업체에서 사용되는 비구면 표현식의 단점을 해결하여 직관적이며 예측가능한 면을 표현할 수 있는 새로운 비구면 표현식, 일명 Q Polynomials (또는 Forbes Polynomials, Q-type Polynomials)을 소개한다. Q Polynomials은 기존 quadratic polynomial을 이용한 표현식과 달리 서로 영향을 미치지 않는 유일한 함수 Qm를 기본으로 하는 다항식으로 구성되어 있기 때문에 각 계수는 하나의 비구면에 대해 유일한 계수다. 각 항의 함수의 모양이 이미 정해져 있기 때문에 계수들의 크기를 살펴보면 비구면도, 측정 가능성, 가공 및 생산 가능성에 대한 예측이 가능하다. 따라서 비구면 설계 시점에서부터 시험/검사, 생산이 실질적으로 가능한 비구면 광학요소인지가 판정되므로 설계시부터 설계자, 시험/검사자, 생산자 사이의 합의가 이루어지는 것과 같다. 따라서 생산성과 간섭계 측정을 이용한 초정밀 비구면를 제조할 수 있는 결과에 이르게 된다. 이미 도입한 여러 업체에서 긍정적인 결과를 얻고 있다. Q polynomials은 기존에 현업에서 사용되고 있는 광학 설계 프로그램에도 적용되어 사용 가능하다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.131-132
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• 2011

This study analyzes the yearly-best delivered size range of truck mixer based on the specified mix, Water to Binder Ratio, aggregate proportion and unit amount with statistical method targeting on Kyeongi and Kyeongsang province and compares with the similar materials of Japan to propose as a basic standard for the quality control of mixer truck. As a result, in case of the Water to Binder Ratio of these areas, it is higher than Japan's due to the excessive safety rate reflecting the changes of differential value impact and unit amount, and the unit amount's standard deviation is very large by reflecting the changes of the amount used and chemical admixture susceptibility. In case of aggregate proportion, the frequency rate is about 50%, which is very similar value with Japan's one.

• International Journal of Knowledge Content Development & Technology
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• 제12권3호
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• pp.19-29
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• 2022

The new age is characterised by information communication technology, where computers, laptops, mobile gadgets such as palmtops, tablets, mobile phones and the internet have made their way to every sphere of life from our domestic environments such a homes, small retail shops, banks to large industries and the world at large. Over time, so many questions about the ethical use of Information and Communication Technology (ICT) have emerged on who has access to what technology and the use of it and like every other technological invention. This paper will look at the morality involved in making use of ICT to promote ethical use of data or information in a virtual environment. ICT also possesses both positive and negative impacts; the questions that these impacts raise are what this piece attempts to answer, providing global scrutiny to these ethical issues, situations and questions; and providing recommendations in line with global best practices.

• 동아시아식생활학회지
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• 제20권4호
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• pp.619-627
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• 2010

Finality in presenting table has an important significance. A presentation method in table comes to have different directionality depending on objective and significance such as the appearance of presentation for the substantial use or the appearance of presentation for delivering message. In our life, the utility table came to have value more than what supplies nutrition. Simultaneously with it, the table came to have the significance as a place of communication. What is being indicated in a different form from this is the art table. The table-coordinate starts to occupy a position in one aesthetic sphere, aside from the functional part of having a meal and communication, and is attempting the entry as the art sphere. What two types have been researched and developed so far in the face of having clear difference is limited to the utility presentation. The utility presentation and the art presentation need to be progressed at the same time rather than being separately classified and thought. Pursuit only for utility leads to being unable to proceed with making a new thing. The art table coordinate will be able to function as the new awakening point in the position of proceeding with such table coordinate. When proceeding with maintaining the form of the existing utility table, a client fails to feel fresh. Thus, coming to give new awareness by integrating art will lead to being available effectively for creating another profit. Even the art table can apply the characteristic of the display table among characteristics of the utility table. The display table aims at creating profit through communication between buyer and seller. Thus, even through the art table, both effects called the occurrence in profit and the initiative in trend will be capable of being enjoyed totally. Accordingly, the presentation of two tables in the art table and the utility table has clearly different characteristic. However, given properly using difference in presentation of the two, the best effect will be possibly seen.

• 대한화장품학회지
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• 제45권4호
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• pp.409-414
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• 2019

실리카와 폴리메틸실세스퀴옥세인(polymethylsilsesquioxane, PMSQ)은 화장품 원료로 널리 쓰이는 실리콘 분체이다. 본 연구팀은 각각 실리카와 PMSQ의 전구체로서 테트라에톡시실란(tetraethyoxysilane, TEOS)과 메틸트라이메톡시실란(methyltrimethoxysilane, MTMS)을 사용하여 졸-겔 법(sol-gel method)을 통해 실리카-PMSQ 복합분체를 합성하였다. 또한, 합성에 사용된 실란 단량체인 TEOS와 MTMS의 단순한 비율 조절만으로 복합분체의 형태 제어에 성공하였다. 실리카-PMSQ 복합분체는 구형, 라즈베리형, 도넛형, 총 3가지 형태를 띠었고, 공통적으로 사용감이 부드럽고 수분산에 용이하며 소프트 포커스 효과를 나타내었다. 복합분체의 형태에 따라서 사용감과 밀착력, 소프트 포커스 효과의 강도에 차이가 있었다. 라즈베리형 복합분체는 가장 강한 소프트 포커스 효과를 보였고, 도넛형 복합분체는 가장 강한 밀착력을 보였으며, 구형 복합분체는 가장 부드러운 사용감을 보였다. 본 연구 결과를 바탕으로, 실리카-PMSQ 복합분체를 원하는 형태로 간편하게 합성할 수 있을 것이다. 더 나아가, 목적에 맞는 복합분체를 선택하여 화장품에 적용할 수 있을 것이다.

• 한국산학기술학회논문지
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• 제20권6호
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• pp.314-321
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• 2019

본 연구에서 개발된 Self-Adaptive Vision Correction Algorithm (SAVCA)은 광학적 특성을 모방하여 개발된 Vision Correction Algorithm (VCA)의 총 6개의 매개변수 중 자가 적응형태로 구축된 Division Rate 1 (DR1) 및 Division Rate 2 (DR2)를 제외한 Modulation Transfer Function Rate (MR), Astigmatic Rate (AR), Astigmatic Factor (AF) 및 Compression Factor (CF) 등 4개의 매개변수를 변경하여 사용성을 증대시키기 위해 제시되었다. 개발된 SAVCA의 검증을 위해 기존 VCA를 적용하였던 2개 변수를 갖는 수학 문제 (Six hump camel back 및 Easton and fenton) 및 30개 변수를 갖는 수학 문제 (Schwefel 및 Hyper sphere)에 적용한 결과 SAVCA는 비교한 다른 알고리즘 (Harmony Search, Water Cycle Algorithm, VCA, Genetic Algorithms with Floating-point representation, Shuffled Complex Evolution algorithm 및 Modified Shuffled Complex Evolution)에 비해 우수한 성능을 보여주었다. 마지막으로 공학 문제인 Speed reducer design에서도 SAVCA는 가장 좋은 결과를 보여주었다. 복잡한 매개변수 조절과정을 거치지 않은 SAVCA는 여러 분야에서 적용이 가능할 것이다.

• 경영과학
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• 제18권1호
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• pp.41-54
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• 2001

In this paper, we proposed a method to determine optimal wave source for mobile telephone communication. The approach is based on wave propagation simulation. Given a wave source we can determine wave propagation effects on every surfaces of wave simulation environment. The effect is evaluated as a cost function while the source’s position x, y, z work as variables for a parameter optimization. Wave propagated 3 dimensional space generates reflected waves whenever it hits boundary surface, it receives multiple waves which are reflected from various boundary surfacers in space. Three algorithms being implemented in this paper are based on a raytracing theory. If we get 3 dimensional geometry input as well as wave sources, we can compute wave propagation effects all over the boundary surfaces. In this paper, we present a new approach to compute wave propagation. First approach is tracing wave from a source. Source is modeled as a sphere casting vectors into various directions. This approach has limit in computing necessary wave propagation effects on all terrain surfaces. The second approach proposed is tracing wave backwards : tracing from a wave receiver to a wave source. For this approach we need to allocate a wave receiver on every terrain surfaces modeled, which requires enormous amount of computing time. But the second approach is useful for indoor wave propagation simulation. The last approach proposed in this paper is tracing sound by geometric computation. We allow direct, 1-relfe tion, and 2-reflection propagation. This approach allow us to save in computation time while achieving reasonable results. but due to the reflection limitaion, this approach works best in outdoor environment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.410-415
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• 2002

In this article, spatial filtering procedures with application to spherical acoustical holography are discussed. Planar and cylindrical holography are the most widely used amongst the various nearfield acoustical holography techniques. However, when the geometry of a source is similar to a sphere, spherical holography may yield better results than other types of holography since there are no errors due to truncation of the sound field in the spherical case. Spatial filtering affects the accuracy of spherical acoustical holography critically, especially in the case of backward projection. Thus spatial filtering is essential for successful application of spherical holography. In the present work, various filtering methods were evaluated in simulations made using sound pressure fields of various types and with different levels of random spatial noise. It was found that a procedure based on eliminating spherical harmonic coefficients that contribute insignificantly to the total sound power of the source gave the best results on average of the different procedures considered here. Spherical holography procedures were also verified experimentally. Reliable results were obtained using the power filtering algorithm. Thus it was concluded that spherical holography combined with power filtering may prove to be a useful tool for noise source identification.

• Carbon letters
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• 제14권4호
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• pp.210-217
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• 2013

The synthesis of carbon nanomaterials (CNMs) by a chemical vapor deposition method using three different plant oils as precursors is presented. Because there are four parameters involved in the synthesis of CNM (i.e., the precursor, reaction temperature of the furnace, catalysts, and the carrier gas), each having three variables, it was decided to use the Taguchi optimization method with the 'the larger the better' concept. The best parameter regarding the yield of carbon varied for each type of precursor oil. It was a temperature of $900^{\circ}C$ + Ni as a catalyst for neem oil; $700^{\circ}C$ + Co for karanja oil and $500^{\circ}C$ + Zn as a catalyst for castor oil. The morphology of the nanocarbon produced was also impacted by different parameters. Neem oil and castor oil produced carbon nanotube (CNT) at $900^{\circ}C$; at lower temperatures, sphere-like structures developed. In contrast, karanja oil produced CNTs at all the assessed temperatures. X-ray diffraction and Raman diffraction analyses confirmed that the nanocarbon (both carbon nano beads and CNTs) produced were graphitic in nature.

• 한국군사과학기술학회지
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• 제17권6호
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• pp.793-799
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• 2014

EO GRD(Ground Resolved Distance) resolution of airborne EO/IR(Electro-Optical/Infrared) sensor is a critical factor in test and evaluation for EO sensor performance. We propose the laboratory measurement set-up for EO GRD by constructing optical collimator which includes integrated sphere, blackbody, equivalent 3-bar target and 6 DOF motion simulator. GRD is measured in the photographic imagery of bar targets by 3 different distances for 3 EO/IR sensors and the measured results were analyzed statistically. We found that at least 7 sheets of imagery are needed in order to obtain meaningful EO GRD. The result of statistical analysis shows that the distribution of the measured GRD is nearly symmetric about the average GRD, and the better imagery ratio above the average GRD is about 40~70%. Also from the best GRD analysis, it is estimated that the design goal for EO GRD should be 30% superior to the required GRD.