• Korean Chemical Engineering Research
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• 제57권2호
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• pp.283-288
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• 2019

Catalytic removal of sulfur compounds from heavy naphtha (HN) was investigated using a combination of an oxidation process using hydrogen peroxide and an adsorption process using granulated activated carbon (GAC) and white eggshell (WES). This study investigated the impact of changing several operating parameters on the desulfurization efficiency. Specifically, the volume ratio of $H_2O_2$ to HN (0.01~0.05), agitation speed ($U_{speed}$) of the water bath shaker ($100-500{\pm}1rpm$), pH of sulfur solution (1~5), amount of adsorbent (0.1~2.5 g), desulfurization temperature ($25{\sim}85{\pm}1^{\circ}C$) and contact time (10~180 minutes) were examined. The results indicate that the desulfurization efficiency resulting from catalytic and adsorption processes of GAC is better than that of WES for oxidation and removing sulfur compounds from HN due to its high surface area. The desulfurization efficiency depends strongly on all investigated operating parameters. The maximum removal efficiency of GAC and WES achieved by this study was 86 and 65, respectively.

• International Journal of Concrete Structures and Materials
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• 제10권2호
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• pp.143-147
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• 2016

In recent years, some modifications were introduced in the stress-strain relationship of the steel in order to develop a more efficient shear model for reinforced concrete members. The last contribution in this sense corresponding to the Refined Compression Field Theory (RCFT, 2009); this theory proposed a steel constitutive model that has account the tension stiffening area prescribed by technical codes, what simplifies all the design process. However, under certain design conditions supported by such codes, the RCFT model does not provide a real (non-complex) solution for the steel yield strain when the prescribed tension stiffening area is considered; then the load-strain response cannot be computed. In this technical note, the tension stiffening area is fixed in order to guarantee the application of the embedded steel constitutive model for all the standard design range.

• International Journal of Internet, Broadcasting and Communication
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• 제9권1호
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• pp.9-17
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• 2017

This paper describes a process of developing commercial real time image recognition system with company. In this paper we will make a system that is combining an empirical kernel map method and conjugate least squares support vector machine in order to represent images in a low-dimensional subspace for real time image recognition. In the traditional approach calculating these eigenspace models, known as traditional PCA method, model must capture all the images needed to build the internal representation. Updating of the existing eigenspace is only possible when all the images must be kept in order to update the eigenspace, requiring a lot of storage capability. Proposed method allows discarding the acquired images immediately after the update. By experimental results we can show that empirical kernel map has similar accuracy compare to traditional batch way eigenspace method and more efficient in memory requirement than traditional one. This experimental result shows that proposed model is suitable for commercial real time image recognition system.

• Journal of applied mathematics & informatics
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• 제7권1호
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• pp.139-159
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• 2000

In this manuscript we study perturbed Newton-like methods for the solution of nonlinear operator equations in a Banach space and their discretized versions in connection with the mesh independence principle. This principle asserts that the behavior of the discretized process is asymptotically the same as that for the original iteration and consequently, the number of steps required by the two processes to converge to within a given tolerance is essentially the same. So far this result has been proved by others using Newton's method for certain classes of boundary value problems and even more generally by considering a Lipschitz uniform discretization. In some of our earlierpapers we extend these results to include Newton-like methods under more general conditions. However, all previous results assume that the iterates can be computed exactly. This is mot true in general. That in why we use perturbed Newton-like methods and even more general conditions. Our results, on the one hand, extend, and on the other hand, make more practical and applicable all previous results.

• 조명전기설비학회논문지
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• 제26권5호
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• pp.71-78
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• 2012

This paper presents a digital control solution to process capacitor current feedback of high performance single-phase UPS for non-linear loads. In all UPS the goal is to maintain the desired output voltage waveform and RMS value over all unknown load conditions and transient response. The proposed UPS uses instantaneous load voltage and filter capacitor current feedback, which is based on the double regulation loop such as the outer voltage control loop and inner current control loop. The proposed DSP-based digital-controlled PWM inverter system has fast dynamic response and low total harmonic distortion (THD) for nonlinear load. The control system was implemented on a 32bit Floating-point DSP controller TMS320C32 and tested on a 5[KVA] IGBT based inverter switching at 11[Khz]. The validity of the proposed scheme is investigated through simulation and experimental results.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.171-174
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• 2006

A large number of service providers in countries all over the world have established GNSS reference station networks in the last years and are using network software today to provide a correction stream to the user as a routine service. In current GNSS network processing, all the geometric related information such as ionospheric free carrier phase ambiguities from all stations and satellites, tropospheric effects, orbit errors, receiver and satellite clock errors are estimated in one centralized Kalman filter. Although this approach provides an optimal solution to the estimation problem, however, the processing time increases cubically with the number of reference stations in the network. Until now one single Personal Computer with Pentium 3.06 GHz CPU can only process data from a network consisting of no more than 50 stations in real time. In order to process data for larger networks in real time and to lower the computational load, a federated filter approach can be considered. The main benefit of this approach is that each local filter runs with reduced number of states and the computation time for the whole system increases only linearly with the number of local sensors, thus significantly reduces the computational load compared to the centralized filter approach. This paper presents the technical aspect and performance analysis of the federated filter approach. Test results show that for a network of 100 reference stations, with the centralized approach, the network processing including ionospheric modeling and network ambiguity fixing needs approximately 60 hours to process 24 hours network data in a 3.06 GHz computer, which means it is impossible to run this network in real time. With the federated filter approach, only less than 1 hour is needed, 66 times faster than the centralized filter approach. The availability and reliability of network processing remain at the same high level.

• 한국콘텐츠학회논문지
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• 제7권4호
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• pp.133-140
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• 2007

기존의 상업적인 3D CG 애니메이션 제작 공정 구조는 부서간의 병목현상으로 모든 부서가 동시에 작업을 할 수 있는 효율적인 구조로 이루어지지 않고 있다. 예를 들어, 애니메이팅 작업을 하기 위해선 선행되어야 할 모델링과 Set-Up 단계가 끝나기 전에는 애니메이팅 작업을 할 수가 없다. 그 결과, 제작 일정의 지연, 제작비의 손실을 발생시키게 되고, 또한 선행된 작업에 수정을 가할 경우 수정이 끝날 때 까지 애니메이팅 작업은 중단된다는 결과를 야기 시킨다. 이런 문제는 표준으로 정해 놓은 "마스터 캐릭터"의 적용으로 도움을 줄 수가 있는데, 프로젝트의 시작과 동시에 모델링과 set-up 그리고 다른 어떤 작업과도 독립적으로 애니메이팅 작업을 시작 할 수 있고 수정 작업도 독립적으로 수행이 가능해서 애니메이션 제작공정을 효율적으로 관리할 수 있다.

• 산업공학
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• 제16권1호
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• pp.8-15
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• 2003

With rapid growth of internet technology, companies have developed an information system such as the electronic catalog for product data in the E-Business. Due to the heuristic nature of the catalog search for proper tools in the specific process, the intelligent and user friendly methods residing in the search process give a comfortable environment even for the beginners in the field. In this paper, we develop a web based catalog for machining tools especially in Milling process. It has two distinct procedures for the users of the catalog; Search and Analysis. The Search is to select a proper cutter, insert, component combination in the developed relational database based on the cutting process and material. The Analysis is to suggest a recommended optimal cutting conditions based on the machining tools and selected materials. All of these procedures are stored in a server with a program based on the ASP and Java Script where the procedure is initiated by the client using the internet which is accessed through insert. With the success on implementing the above engineering database in the internet, we can provide the foundation for developing PDM with heuristic procedure.

• 반도체디스플레이기술학회지
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• 제20권2호
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• pp.126-130
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• 2021

The ball grid array is one of the packaging methods that used in high density printed circuit board. Solder void defects caused by voids in the solder ball during the BGA process do not directly affect the reliability of the product, but it may accelerate the aging of the device on the PCB layer or interface surface depending on its size or location. Void inspection is important because it is related in yields with products. The most important process in the optical inspection of solder void is the segmentation process of solder and void. However, there are several segmentation algorithms for the vision inspection, it is impossible to inspect all of images ideally. When X-Ray images with poor contrast and high level of noise become difficult to perform image processing for vision inspection in terms of software programming. This paper suggests the solution to deal with the suggested problem by means of using Mask R-CNN instead of digital image processing algorithm. Mask R-CNN model can be trained with images pre-processed to increase contrast or alleviate noises. With this process, it provides more efficient system about complex object segmentation than conventional system.

• 한국게임학회 논문지
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• 제4권2호
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• pp.13-20
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• 2004

우리는 도망자-추적자 게임 풀이에 관심이 많다. 도망자가 추적자를 피해 미로를 탈출하는 게임이다. 도망자가 추적자를 유인하기도 하고 벽을 이용해 교묘히 피하기도 한다. 경험에 의하면 수작업으로 풀기에는 매우 어려운 단계들도 있었다. 게임을 풀기 위한 방법으로 모델 체킹 기법을 사용하였다. 모델 체킹은 게임의 모든 상태 공간을 넓이 우선 방식으로 철저하게 탐색하기 때문에 게임을 풀 수 있는 가장 짧은 경로인 최적의 답을 구할 수 있다. 다행히 풀이 과정에서 상태 폭발 문제는 일어나지 않았고, 게임 풀이 결과를 임베디드 시스템인 레고 마인드스톰에 응용하였다. 도망자, 추적자에 해당하는 두 대의 에이전트를 만들어 게임을 구현하고 실험하여 풀이가 정확한 지를 실제 확인할 수 있었다.