• Journal of environmental and Sanitary engineering
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• v.19 no.4 s.54
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• pp.19-24
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• 2004

The objective of this study was to develop a mechanistically based mathematical model that would consider the interdependence of VOCs transport, microbial activity, and sorptive interactions in a moist, unsaturated soil. Because the focus of the model was on description of natural attenuation, the advective VOCs transport that is induced in engineered remediation processes such as vapor extraction was not considered. The utility of the model was assessed through its ability to describe experimental observations from diffusion experiments using toluene as a representative VOCs in well-defined soil columns that contained a toluene degrading bacterium, Pseudomonas putida G7 md Fl, as the sole active microbial species. The gas-liquid mass-transfer was found to be a key parameter controlling the ability of bacteria to degrade VOCs. This finding indicates that soil size and geometry are likely to be important parameters in assessing the possible success of natural attenuation of VOCs in contaminated unsaturated soils. Therefore we found that Pseudomonas putida G7 and Fl were very effective to remove of refractory pollutants such as toluene in soil by Bio-filter

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.1
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• pp.76-80
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• 2010

It is floating to security of information and the early assignment that it is important it processes and to transmit in inundations of information that I changed suddenly. I used the encryption/decryption process that applied simple substitution and mathematical calculation algorithm at theory and encryption transmission steps protective early information. Hardware and financial loss are using spurious random number to be satisfied with the random number anger that isn't real random number to size so much perfect information protection using One-time pad for applying this. I was transformed into serial test under a test to prove spurious random number anger, and it is into random number anger stronger, and the transformation serial test that proposes is proving it in algorithm speed and efficiency planes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.4
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• pp.1376-1384
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• 1996

Measuring the velocity of fluid flow, semiconductor flow sensors are widely used in the various fields of engineering and science such as the semiconductor manufacturing processes and electronic control engines for automobiles. In the near future, this type of sensors will replace present hot wire type sensors or other type flow sensor due to its low price, easy handling and small size. To develop the advanced semiconductor flow sensor, it is necessary to obtain characteristics of the flow and the heat transfer around the sensor in advance. In the present study, the theoretical analysis including mathematical modeling and numerical calculation to predict the characteristics of heat transfer and flow field around the sensor was carried out. The main parameters for optimum design of the flow sensor are the free stream velocity, the heat generation rate of silicon arm and the distance between arms. Effects of these parameters on flow and heat transfer around the sensor and the temperature difference between arms are examined.

• Journal of Communications and Networks
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• v.18 no.6
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• pp.926-937
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• 2016

In this paper, we study the feasibility of receiver diversity for application to downlink cellular networks, where low-energy devices are equipped with information decoding and energy harvesting receivers for simultaneous wireless information and power transfer. We compare several options that are based on selection combining and maximum ratio combining, which provide different implementation complexities. By capitalizing on the Frechet inequality, we shed light on the advantages and limitations of each scheme as a function of the transmission rate and harvested power that need to be fulfilled at the low-energy devices. Our analysis shows that no scheme outperforms the others for every system setup. It suggests, on the other hand, that the low-energy devices need to operate in an adaptive fashion, by choosing the receiver diversity scheme as a function of the imposed requirements. With the aid of stochastic geometry, we introduce mathematical frameworks for system-level analysis. We show that they constitute an important tool for system-level optimization and, in particular, for identifying the diversity scheme that optimizes wireless information and power transmission as a function of a sensible set of parameters. Monte Carlo simulations are used to validate our findings and to illustrate the trade-off that emerge in cellular networks with simultaneous wireless information and power transfer.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.1
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• pp.44-51
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• 2016

Recently, artificial intelligence has reached the level of top information technologies that will have significant influence over many aspects of our future lifestyles. In particular, in the fields of machine learning technologies for classification and decision-making, there have been a lot of research efforts for solving estimation and control problems that appear in the various kinds of portfolio management problems via data-driven approaches. Note that these modern data-driven approaches, which try to find solutions to the problems based on relevant empirical data rather than mathematical analyses, are useful particularly in practical application domains. In this paper, we consider some applications of modern data-driven machine learning methods for portfolio management problems. More precisely, we apply a simplified version of the sparse Gaussian process (GP) classification method for classifying users' sensitivity with respect to financial risk, and then present two portfolio management issues in which the GP application results can be useful. Experimental results show that the GP applications work well in handling simulated data sets.

• Journal of the Korea Furniture Society
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• v.27 no.2
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• pp.128-136
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• 2016

Digital designs that appear in the three-dimensional virtual space by the digital type are designed as there is not an image created with an organic artificially generated (Creation) and representation (Modifying), developed by the specific environment given. The advanced digital design will produce a result with an algorithm according to a mathematical operation and the environment and has the nature of generating the real world, changes, development and affinity (Genetic Process). The digital design process is largely defined by a set of processes that are consistently designed to integrate form of creation, reproduction, proceeds in three steps, while the manufacture and assembly as a form of maintenance as possible the intended form of control data from the concept of building. By Joris Laarman 3D printer design is a simulation created by the digital process by the various algorithms and design achieved through the development of 3D printers, such as new materials and MX3D. From the mold production of a complex whole by using a robot and other digital production tool extracts a variety of forms.

• Journal for History of Mathematics
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• v.27 no.3
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• pp.155-164
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• 2014

Tianyuanshu and Zengcheng Kaifangfa introduced in the Song-Yuan dynasties and their contribution to the theory of equations are one of the most important achievements in the history of Chinese mathematics. Furthermore, they became the most fundamental subject in the history of East Asian mathematics as well. The operations, or the mathematical structure of polynomials have been overlooked by traditional mathematics books. Investigation of GuIlJib (九一集) of Joseon mathematician Hong JeongHa reveals that Hong's approach to polynomials is highly structural. For the expansion of $\prod_{k=11}^{n}(x+a_k)$, Hong invented a new method which we name Hong JeongHa's synthetic expansion. Using this, he reveals that the processes in Zhengcheng Kaifangfa is not synthetic division but synthetic expansion.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.5
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• pp.33-41
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• 2018

Most important thing when designing and implementing a supply chain network is to consider various problems which may occur in real world situation. In this paper, we propose a supply chain network considering two problems (environmental factor and transportation types) under real world situation. CO2 emission amount as environmental factor is considered since it is usually generated from production and transportation processes. Normal delivery, direct delivery and direct shipment as transportation types are also considered since many customers ask various transportation types for delivery or shipment of their products under on-line or off-line purchase environment. The proposed supply chain network considering environmental factor and transportation types is represented in a mathematical formulation and implemented using hybrid genetic algorithm (HGA) approach. In numerical experiments, several scales of supply chain networks are presented and implemented using HGA approach. The performance of the HGA approach is compared with those of some conventional approaches under various measures of performance. Finally, it is proved that the performance of the HGA approach is superior to those of the others.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.1
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• pp.33-42
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• 1997

The reciprocating compressors are widely used in industrial fields for its simplicity in principle and high efficiency. But the design of it requires rigorous experiments due to its high dependence on many design parameters. In this work, a mathematical model is developed so that we can analyze the gas-solid interaction during the whole working processes of a reciprocating compressor. The governing equations, which represent the fluid-solid interaction, was derived from the unsteady Bernoulli's equation with the assumption of quasi-steady working process. The valve itself was assumed to be a one degree of freedom spring-mass-damper system. A simple thermodynamic relation, the ideal gas state equation, was used to give it an external force term assuming that the refrigerant behaves like an ideal gas. It was suggested to use a motor of higher driving frequency to enhance the performance of the reciprocating compressor without causing a faster failure of the valve.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.239-244
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• 2011

In this paper, we analyzed the electrical characteristics with crack pattern in crystalline solar cell. crystalline solar cells with a thin substrate, even small shocks can be easily damaged. Before the module goes through many processes, because the solar cells are at risk of a crack. That occurred early in the PV module micro-crack is not easily detection by eye test or output test. Because the EL (Electroluminescence) device has been detected using. PV module is made by laminated of a variety of materials. By different properties of each material will affect the crack. For this reason, the crack will grow and affect the output. And We analyzed the three crack patterns in crystalline solar cell. A growth of cracks on crystalline solar cell was interpreted by analysing generated cracks on the PV modules. Based on this interpretation, an electrical output value was calculated by mathematical modeling on electrical output characteristic with each crack patterns.