• Journal of applied mathematics & informatics
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• 제29권3_4호
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• pp.949-953
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• 2011

It is interesting to know the behavior of a network from its structure. One interesting topic is to find a relation between the existence of a positive equilibrium of the reaction network and its structure. One approach to study this topic is using the concept of deficiency. Another is using some conditions on nodes, which can apply to large-size networks compared to deficiency. In this work, we show the relation between deficiency and the conditions.

• Journal of applied mathematics & informatics
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• 제28권5_6호
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• pp.1545-1552
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• 2010

It is interesting to know the behavior of a network from its structure. One interesting topic is to find a relation between the existence of a positive equilibrium of the reaction network and its structure. One approach to study this topic is using the concept of deficiency. In this work, we develop an algorithm and show an elementary proof of the relation based on the algorithm and deficiency.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.462-463
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• 2006

Monodispersed and nano-sized Ni powders were synthesized from aqueous nickel sulfate hexahydrate $(NiSO_4{\cdot}6H_2O)$ inside nonionic polymer network by using wet chemical reduction process. The sucrose was used as a nonionic polymer network source. The effect of reaction conditions such as the amount of sucrose and a various reaction temperature, nickel sulfate hexahydrate molarity. The influence of a nonionic polymer network on the particle size of the prepared Ni powders was characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and particle size analysis (PSA). The results showed that the obtained Ni powders were strong by dependent of the reaction conditions. In particular, the Ni powders prepared inside a nonionic polymer network had smooth spherical shape and narrow particle size distribution.

• 한국산업융합학회 논문집
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• 제22권2호
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• pp.87-93
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• 2019

This research deals with posture optimization for humanoid robot against external forces using genetic algorithm and neural network. When the robot takes a motion to push an object, the torque of each joint is generated by reaction force at the palm. This study aims to optimize the posture of the humanoid robot that will change this torque. This study finds an optimized posture using a genetic algorithm such that torques are evenly distributed over the all joints. Then, a number of different optimized postures are generated from various the reaction forces at the palm. The data is to be used as training data of MLP(Multi-Layer Perceptron) neural network with BP(Back Propagation) learning algorithm. Humanoid robot can find the optimal posture at different reaction forces in real time using the trained neural network include non-training data.

• Journal of applied mathematics & informatics
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• 제30권5_6호
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• pp.787-792
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• 2012

We present a graphical algorithm and theorems for calculating the ranks of reaction networks. The ranks are needed to study behaviors of the networks from their structures. This approach can graphically simplify complex networks for the calculation. We show an example of a large network for the practical advantage.

• International Journal of Computer Science & Network Security
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• 제22권6호
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• pp.91-96
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• 2022

The photocatalytic degradation of salicylic acid takes place in several stages involving coupled phenomena, such as the transport of molecules and the chemical reaction. The systems of transport equations and the photocatalytic reaction are numerically solved using COMSOL Mutiphysics (CM) simulation software. CM will make it possible to couple the phenomena of flow, the transport of pollutants (salicylic acid) by convection and diffusion, and the chemical reaction to the catalytic area (bauxite or TiO2 doped by nanoparticles). The simulation of the conversion rate allows to correctly fit the experimental results. The temporal simulation shows that the reaction reaches equilibrium after a transitional stage lasting over one minute. The outcomes of the study highlight the importance of diffusion in the boundary layer and the usefulness of injecting micro-agitation into the microchannel flow. Under such conditions, salicylic acid degrades completely.

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권4호
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• pp.257-262
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• 2003

A straightforward and effective method is presented for immobilizing enzymes on a microchip platform without chemically modifying a micro-channel or technically microfabricating a column reactor and fluid channel network. The proposed method consists of three steps: the reconstitution of a nitrocellulose (NC) membrane on a plane substrate without a channel network, enzyme immobilization on the NC membrane, and the assembly of another substrate with a fabricated channel network. As a result, enzymes can be stably and efficiently immobilized on a microchip. To evaluate the proposed method, two kinds of enzymatic reaction are applied: a sequential two-step reaction by one enzyme, alkaline phosphatase, and a coupled reaction by two enzymes, glucose oxidase and peroxidase, for a glucose assay.

• 한국컴퓨터정보학회논문지
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• 제20권2호
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• pp.47-54
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• 2015

관객의 감정 반응은 개별 관객들의 반응을 관측하여 판단할 수 있다. 영상 카메라를 이용한 시각적 데이터를 분석하여 활용하는 방법을 이용할 경우, 관객의 반응을 적은 비용으로 데이터를 추출하여 판단할 수 있는 것이 가능하다. 하지만, 영상 카메라를 이용할 경우 다수의 관객으로부터 발생하는 대규모의 영상 신호로부터 관객의 특징값들을 분석하여 반응을 판단하기 위한 방법과 시스템이 필요하다. 이를 위해 본 논문에서는 관객의 영상 데이터를 신경회로망 기법을 이용하여 관객의 반응을 관측하여 판단하는 방법과 시스템을 제안하고, 기존의 관객석을 고정적인 영역으로 분할하여 데이터를 취합하여 분석하기 때문에 발생하는 문제를 개선하기 위해 얼굴 검출을 통해 자동적으로 관객 영역을 분할하는 방법을 제안한다. 또한 실험을 통해 기존의 고정적으로 관객 영역을 지정하는 방법에 비해 10.5 %(7.75의 Hit Ratio)의 성능향상이 있음을 확인하였다. 이를 통해 제안하는 방법이 실제 관객 반응을 판단하는데 더 적합하다는 것을 알 수 있다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제16권6호
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• pp.46-57
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• 2011

In this study, analytical solution of multip-species transport equations coupled with a first-order reaction network under constant concentration boundary condition or total flux boundary condition is obtained using similarity transformation approach of Clement et al. (2000). The study shows the schematic process about how multi-species transport equations with first-order sequential reaction network is transformed through the similarity transformation approach into independent and uncoupled single species transport equations with first-order reaction. The analytical solution was verified through the comparison with popular commercial programs such as 2DFATMIC and RT3D. The analytical solution can be utilized in nuclear waste sites where radioactive contaminants and their daughter products occur and in industrial complex cities where chlorinated solvent such as PCE, TCE, and its biodegradation products produces. In addition, it can help the verification of the developed numerical code.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.317-320
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• 1997

In the water purification plant, chemicals are injected for quick purification of raw water. It is clear that the amount of chemicals intrinsically depends on the water quality such as turbidity, temperature, pH and alkalinity etc. However, the process of chemical reaction to improve water quality by the chemicals is not yet fully clarified nor quantified. The feedback signal in the process of coagulant dosage, which should be measured (through the sensor of the plant) to compute the appropriate amount of chemicals, is also not available. Most traditional methods focus on judging the conditions of purifying reaction and determine the amounts of chemicals through manual operation of field experts or jar-test results. This paper presents the method of deriving the optimum dosing rate of coagulant, PAC(Polymerized Aluminium Chloride) for coagulant dosing process in water purification system. A neural network model is developed for coagulant dosing and purifying process. The optimum coagulant dosing rate can be derived the neural network model. Conventionally, four input variables (turbidity, temperature, pH, alkalinity of raw water) are known to be related to the process, while considering the relationships to the reaction of coagulation and flocculation. Also, the turbidity in flocculator is regarded as a new input variable. And the genetic algorithm is utilized to identify the neural network structure. The ability of the proposed scheme validated through the field test is proved to be of considerable practical value.