• The Korean Journal of Applied Statistics
• /
• v.23 no.1
• /
• pp.197-206
• /
• 2010

In this paper, we propose boosting algorithms when data are very large or coming in batches sequentially over time. In this situation, ordinary boosting algorithm may be inappropriate because it requires the availability of all of the training set at once. To apply to large scale data or data batch stream, we modify the AdaBoost and Arc-x4. These algorithms have good results for both large scale data and data batch stream with or without concept drift on simulated data and real data sets.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.833-836
• /
• 1998

The propose of this paper is to implement the master slave control with non-actuated Master Arm scheme by using spaceball. The spaceball is a device which can receive all 6-DOF at once and was selected because it isn't dependent to robot type or it's DOF but can be used to produce information about 3D coordiante system The proposed method's main benefit is that one who has no idea about robot structure can control the manipulator with easy. The simulation is supported with 3 modes of control to accomodate unexpected situation. The proposed implementation has probed that a non-trained user can manipulate the slave with intuition without much difficults.

• Journal of Korean Institute of Industrial Engineers
• /
• v.16 no.2
• /
• pp.71-79
• /
• 1990

In this paper, the Double Shortest Arborescence & Merging method is presented as an efficient heuristic algorithm for the Public Vehicle Routing Problem which is to find the minimum total cost routes of M or less vehicles to traverse the required arcs(demand streets) at least once and return to their starting depot on a directed network. Double Shortest Arborescence which consists of forward shortest aborescence and backward one informs M or less shortest routes to traverse all required arcs. The number of these routes is reduced to M or less by merging routes. The computational experiment based on randomly generated networks reports that this algorithm is efficient.

• Proceedings of the KSME Conference
• /
• 2000.11a
• /
• pp.818-823
• /
• 2000

In practical design studies, most of designers solve multidisciplinary problems with complex design structure. These multidisciplinary problems have hundreds of analysis and thousands of variables. The sequence of process to solve these problems affects the speed of total design cycle. Thus it is very important for designer to reorder original design processes to minimize total cost and time. This is accomplished by decomposing large multidisciplinary problem into several multidisciplinary analysis subsystem (MDASS) and processing it in parallel. This paper proposes new strategy for parallel decomposition of multidisciplinary problem to raise design efficiency by using genetic algorithm and shows the relationship between decomposition and multidisciplinary design optimization (MDO) methodology.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.20 no.43
• /
• pp.321-331
• /
• 1997

Measurement of attributes is often highly subjective and imprecise, yet most MADM methods lack provisions for handling imprecise data. Frequently, decision makers must establish a ranking within a finite set of alternatives with respect to multiple attributes which have varying degrees of importance. The problem is more complex if the evaluations of alternatives according to each attribute are not expressed in precise numbers, but rather in fuzzy numbers. Analysis must allow for lack of precision and partial truth. The advantages of a fuzzy approach for MADM are that a decision maker can obtain efficient solutions all at once without trial and error, and that this approach provides better support for judging the interactive improvement of solutions in comparison with o decision making method. The algorithm used in this study is based on the concepts of vague set theory. Linguistic variables and vague values are used to facilitate a decision maker's subjective assessment about attribute weightings and the appropriateness of alternative versus selection attributes in order to obtain final scores which are called vague appropriateness indices. A numerical example is presented to show the practical applicability of this approach.

• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 2006.11a
• /
• pp.386-391
• /
• 2006

Though a variety of demands for an green dwelling, it is hard to diffuse a wooden house due to high construction cost. So this study aims to diffuse to propose a space modular for production and supply. Therefore the result of investigation to the space modular of each room through the survey of width and depth in the type of dwelling in korea is as follows. 1) Investigated the mixture of magnitude on the total width and depth, the survey is showed commonly 3.6m and 4.2m. 2) Once the depth is 3.6m, a living room and inner room, room's width is 3.9m, 4.5m. Once the depth is 4.2m, those width is 4.8m. 3) By use of a survey, the post distances consisted of all rooms are 3.6m, 3.9m, 4.2m, 4.5m, 4.8m. The result of investigation to possibility for mixture applied to six level types invested post modules to the wooden house of post & Beam method is as follows. 1) With the regularity of depth and simplicity of width, It is potential to compound floor plan in korea. 2) It is possible to plan an informal shape of kitchen+dining room which is a spare space available for the merit changeable space after arranged main rooms. 3) It is possible to plan a space through a variety of mixture method at bathroom. Thus, it is possible for a variety of floor formations to build a low-cost wooden house through five types of post distance.

• Smart Structures and Systems
• /
• v.6 no.5_6
• /
• pp.675-687
• /
• 2010

Structural Health Monitoring (SHM) is the science and technology of monitoring and assessing the condition of aerospace, civil and mechanical infrastructures using a sensing system integrated into the structure. Impedance-based SHM measures impedance of a structure using a PZT (Lead Zirconate Titanate) patch. This paper presents a low-power wireless autonomous and active SHM node called Autonomous SHM Sensor 2 (ASN-2), which is based on the impedance method. In this study, we incorporated three methods to save power. First, entire data processing is performed on-board, which minimizes radio transmission time. Considering that the radio of a wireless sensor node consumes the highest power among all modules, reduction of the transmission time saves substantial power. Second, a rectangular pulse train is used to excite a PZT patch instead of a sinusoidal wave. This eliminates a digital-to-analog converter and reduces the memory space. Third, ASN-2 senses the phase of the response signal instead of the magnitude. Sensing the phase of the signal eliminates an analog-to-digital converter and Fast Fourier Transform operation, which not only saves power, but also enables us to use a low-end low-power processor. Our SHM sensor node ASN-2 is implemented using a TI MSP430 microcontroller evaluation board. A cluster of ASN-2 nodes forms a wireless network. Each node wakes up at a predetermined interval, such as once in four hours, performs an SHM operation, reports the result to the central node wirelessly, and returns to sleep. The power consumption of our ASN-2 is 0.15 mW during the inactive mode and 18 mW during the active mode. Each SHM operation takes about 13 seconds to consume 236 mJ. When our ASN-2 operates once in every four hours, it is estimated to run for about 2.5 years with two AAA-size batteries ignoring the internal battery leakage.

• Transactions of the Korean hydrogen and new energy society
• /
• v.27 no.1
• /
• pp.127-134
• /
• 2016

Most of reconstruction algorithms for the calculation of temperature distributions in CT (computed tomography)-TDLAS (tunable diode laser absorption spectroscopy) are based upon two-line thermometry method. This method gives unstable calculation convergence due to signal noise, bias error, and signal mis-matches. In this study, a new reconstruction algorithm based on cross-correlation for temperature calculation is proposed. The patterns of the optical signals at all wave lengths were used to reconstruct the temperature distribution. Numerical test has been made using phantom temperature distributions. Using these phantom temperature data, absorption spectra for all wave lengths were constructed, and these spectra were regarded as the signals that would be obtained in an actual experiments. Using these virtually generated experimental signals, temperature distribution was once again reconstructed, and was compared with those of the original phantom data. Calculation errors obtained by the newly proposed algorithm were slightly large at high temperatures with small errors at low temperature.

• Journal of Conservation Science
• /
• v.6 no.2 s.8
• /
• pp.141-148
• /
• 1997

When we have entered high economic growth since 1970s, many archaeological excavations were performed all over the country. Excavated objects composed of variable materials are inevitably subjected to deformations owing to surrounding environments and storage conditions. Although the importance of conservation treatment of the objects is greatly increased, a few conservation laboratories are there comparing with excavation groups. The metallic objects excavated are very unstable and deformable state. So it is important not to allow iron objects, especially cast iron, to dry out once excavated. Because the corrosion reactions on the surface proceed rapidly, the objects may be destroyed at the moment. The conservation procedures of the excavated metallic objects are as follows: (1)It is stable on-site storage method for objects to keep vinyl film with envelop or to immerse alkaline solution to prevent the environmental changes. (2)The objects must be treated at once under suitable methods in the conservation laboratory after excavation. (3)The continued existence of objects depends on environmental factors such as relative humidities, regular inspection, light etc.

• Journal of KSNVE
• /
• v.8 no.2
• /
• pp.267-273
• /
• 1998

This study aims at performing sensitivity analysis of piezoelectric smart structure for minimizing radiated noise from the structure, The structure consists of a flat plate on which disk shaped piezoelectric actuator is mounted, and finite element modeling is used for the structure. The finite element modeling uses a combination of three dimensional piezoelectric, flat shell and transition elements so thus it can take into account the coupling effects of the piezoelectric device precisely and it can also reduce the degrees of freedom of the finite element model. Electric potential on the piezoelectric actuator is taken as a design variable and total radiated power of the structure is chosen as an objective function. The objective function can be represented as Rayleigh's integral equation and is a function of normal displacements of the structure. For the convenience of computation, all degrees of freedom of the finite element equation is condensed out except the normal displacements of the structure. To perform the design sensitivity analysis, the derivative of the objective function with respect to the normal displacements is found, and the derivative of the norma displacements with respect to the design variable is calculated from the finite element equation by using so called the adjoint variable method. The analysis results are compared with those of the finite difference method, and shows a good agreement. This sensitivity analysis is faster and more accurate than the finite difference method. Once the sensitivity analysis program is used for gradient-based optimizations, one could achieve a better convergence rate than non-derivative methods for optimal design of piezoelectric smart structures.