• Polymer(Korea)
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• v.25 no.6
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• pp.826-832
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• 2001

In this study, PPy/gold/mylar type electroactive bi-layer actuator was prepared by the electrochemical polymerization of pyrrole onto the gold/mylar film and the actuation characteristics were studied using bending beam method. Conducting polymer-based actuators undergo volumetric changes due to the movement of dopant ions into the film during the electrical oxidation process. The bilayer films exhibited different actuation characteristics depending on dopant ion size. It was observed that the relatively small dopant ion (i.e. toluene sulfonate) moved into the PPy film at oxidized state, so volume expanded to result in bending motion. In case of the film having large dopant ion (i.e. dodecylbenzenesulfonate), volume expansion was observed at reduced state. This is due to the incorporation of $Na^+$ counterion with water molecules, while the large dopant ion was fixed in the film due to the limited mobility during tile redox process.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2087-2092
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• 2005

Using disturbance observer (DOB) is effective in enhancing the performance of dynamic system in the presence of disturbances. Recently the definition of disturbance has been expanded to modeling uncertainty including parameter variation, internal disturbance. Various structures of DOB have been proposed to improve sensitivity of system for better disturbance rejection performance. However in the case of improvement of sensitivity function, it tends to bring poor transient response due to cross-coupling and phase lag. Furthermore it could be very sensitive to measurement noise due to increased peak of complementary sensitivity function. In this paper, a dual disturbance observer (Dual-DOB) is proposed to reduce the effect of such cross-coupling. It is possible for us to improve the sensitivity function with additional external DOB with hardly affecting complementary sensitivity function. Thus it is able to have robustness against measurement noise. Since we are able to design DOBs of internal and external loop independently, we could prevent transient response quality from degrading while improving the sensitivity function. The proposed Dual-DOB is applied to a commercial optical disk drive tracking servo system. The experimental result shows that the Dual-DOB is an effective method in rejecting the disturbance as well as improving the tracking performance.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2237-2242
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• 2005

The original RRT is iteratively expanded by applying control inputs that drive the system slightly toward randomly-selected states, as opposed to requiring point-to-point convergence, as in the probabilistic roadmap approach. It is generally known that the performance of RRTs can be improved depending on the selection of the metrics in choosing the nearest vertex and bias techniques in choosing random states. We designed a path planning algorithm based on the RRT method for a remote-controlled mobile robot. First, we considered a bias technique that is goal-biased Gaussian random distribution along the command directions. Secondly, we selected the metric based on a weighted Euclidean distance of random states and a weighted distance from the goal region. It can save the effort to explore the unnecessary regions and help the mobile robot to find a feasible trajectory as fast as possible. Finally, the constraints of the actuator should be considered to apply the algorithm to physical mobile robots, so we select control inputs distributed with commanded inputs and constrained by the maximum rate of input change instead of random inputs. Simulation results demonstrate that the proposed algorithm is significantly more efficient for planning than a basic RRT planner. It reduces the computational time needed to find a feasible trajectory and can be practically implemented in a remote-controlled mobile robot.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1594-1597
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• 2005

A rapid development and a wide use of the Internet have expanded a network environment. Further, the network environment has become more complex due to a simple and convenient network connection and various services of the Internet. However, the Internet has been constantly exposed to the danger of various network attacks such as a virus, a hacking, a system intrusion, a system manager authority acquisition, an intrusion cover-up and the like. As a result, a network security technology such as a virus vaccine, a firewall, an integrated security management, an intrusion detection system, and the like are required in order to handle the security problems of Internet. Accordingly, a router, which is a key component of the Internet, controls a data packet flow in a network and determines an optimal path thereof so as to reach an appropriate destination. An error of the router or an attack against the router can damage an entire network. This paper relates to a method for RSMS (router security management system) for secure networking based on a security policy. Security router provides functions of a packet filtering, an authentication, an access control, an intrusion analysis and an audit trail in a kernel region. Security policy has the definition of security function against a network intrusion.

• Journal of architectural history
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• v.7 no.1 s.14
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• pp.31-48
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• 1998

Soengyo-jang has some characteristics as the most great house, the special functions, and the non-regional type of house form. And it has constructed continuously for two centuries by many owners in the different generations, It needs a special research method ; which are consist of a) comprehension of background information from documents and oral instructed materials, b) pursuit of design process through the building survey, and c) theoretical interpretation about 'collectivism'. From the results of this research, it is revealed that the architectural purpose of this house was constructing 'a great manor'. At first phase, it had been a single ordinary house, at second, it had expanded to a complex including many housing clusters, and finally became to expand its dwelling territory into whole village. Its expansion was progressed by the four collecting phases of which were building, building cluster, group of clusters, and topological setting. Main design elements operated in each of collecting phases ; they were partial element of , exterior spaces of , a linear building of , and a pavilion of . The last two elements were also powerful datum.

• International Journal of Reliability and Applications
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• v.1 no.1
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• pp.1-14
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• 2000

The global marketplace is highly competitive and organisations, who want to survive long-term, have to continuously improve, change and adapt in response to market demands. These improvements should focus on cost cutting, increasing productivity levels and quality and guaranteeing deliveries in order to satisfy customers. Total Productive Maintenance (TPM) is one method, which can be used to achieve these goals. TPM is a change management approach that involves employees from both production and maintenance departments. The purpose is to eliminate major production losses by introducing a program of continuous and systematic improvements to production equipment. TPM should be developed and expanded to embrace the whole organisation and all employees should be involved in the process as members of improvement teams. This paper gives a short description of the development of TPM and the TPM implementation process. Findings are reported from a case study in which one of the authors had the possibility of following and guiding a company through their TPM implementation. The implementation process takes several years and the research has focused on the initial three years. The study demonstrates that driving forces, obstacles and difficulties often are dependent on the organisation, its managers and the individual employees.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.1
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• pp.74-82
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• 1999

We proposed an efficient beam Propagation Method(BPM) algorithm for 3-D analysis, which can handle great amount of data on PC efficiently. The new algorithm, which is an expanded version of DuFort-Frankel algorithm for 3-D analysis, can reduce the number of computations for a given BPM analysis. The algorithm was applied to a rib-type directional coupler to find the same results as those from the coupled mode theory.

• Journal of IKEEE
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• v.8 no.1 s.14
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• pp.1-11
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• 2004

This paper proposes new multiplicative techniques over finite field, by using KOA. At first, we regenerate the given polynomial into a binomial or a trinomial to apply our polynomial multiplicative techniques. After this, the product polynomial is archived by defined auxiliary polynomials. To perform multiplication over $GF(2^m)$ by product polynomial, a new mod $F({\alpha})$ method is induced. Using the proposed operation techniques, multiplicative circuits over $GF(2^m)$ are constructed. We compare our circuit with the previous one as proposed by Parr. Since Parr's work is premised on $GF((2^4)^n)$, it will not apply to general cases. On the other hand, the our work more expanded adaptive field in case m=3n.

• International Journal of Advanced Culture Technology
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• v.5 no.2
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• pp.82-89
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• 2017

The range of problems that can be handled by the activation of big data and the development of hardware has been rapidly expanded and machine learning such as deep learning has become a very versatile technology. In this paper, mnist data set is used as experimental data, and the Cross Entropy function is used as a loss model for evaluating the efficiency of machine learning, and the value of the loss function in the steepest descent method is We applied the GradientDescentOptimize algorithm to minimize and updated weight and bias via backpropagation. In this way we analyze optimal reliability value corresponding to the number of exercises and optimal reliability value without overfitting. And comparing the overfitting time according to the number of data changes based on the number of training times, when the training frequency was 1110 times, we obtained the result of 92%, which is the optimal reliability value without overfitting.

• The Korean Journal of Food And Nutrition
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• v.3 no.1
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• pp.69-79
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• 1990

Koryo(918-1352) made a certain progress in her culture and agriculture except the latter part of the era when the development in social economy were retarded due to military dictatorship and Mongol invasion. Despite of these external conditions, cultivations and kinds of horticulture foods were expanded With the help Of many king's agriculture first policy and the advancement in cultivating method . Among the horticulture foods, fruits such as peach, plum, Japanese apricot, apricot, cherry, pear, persimmon, pomegranate, crab apple, Jujube, grape, Chinese quince, walnut, orange, yuzu, chestnut, ginkgo nut(silvernut), pine nut, nutmeg nut, and fiat were crowed, and vegetables such as Chinese cabbage, turnip, radish, garlic, welsh onion, gynmigit, scallion, taro, malva, cucumber, white gourd, bottle gourd, water melon, eggplant, Japanese ginger, ginger and litchi were cultivated, while semi, water shieled and bamboo sprouts were taken in natural. Fruits were taken in natural or through dry, and particularly grapes were used to make wine, Flowers of Japanese apricots, some fruit trees, and chrysanthemum were also made into wine. Certain fruits were used as medicine owing to its medicinal nature. Vegetables were used to make Kimchi or to boil soup, sometimes they were dried to be kept in storage to be used in rare season and also used as medicine Increase in kinds of horticulture foods does not have any direct relation with the reform of social economy, but the fact that so many kinds of horticulture foods were cultivated and used in Koryo era shows that they elevated people's life and dietary culture.