• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1350-1354
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• 2007

As the importance of low power design is emphasized, power consumption became one of the standards that represent the performance of the system. The purpose of this study is to decide design variable that minimize power consumption for the oxygen concentrator in two bed-one compressor 8 step PSA process that has above 90% purity at 3lpm by using given constants and selected parameters. Setting selected parameters as cycle time and equalization time, optimization for PSA process in the oxygen concentrator is progressed. For this, we need to know the features and basic principals of PSA process and to deduce objective function of performance analysis. Validations for objective function and lots of experiments are needed too. By using the characteristic curve of the compressor and the pressure curve of the process for 1 cycle, objective function was set. After theoretical 2 dimensional optimized paths was obtained. And then, by experiment, theoretical optimized path was verified.

• Korean Institute of Interior Design Journal
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• no.3
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• pp.78-84
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• 1994

The theory of Place is based on the relations of human being, environment and architecture in the view of the existentialism and phenomenology. A place has two respects, the one is Natural place as landscape and the other is Man-made place as city, public building , private house. These properties of place are appeared through axis , directions, boundaries, centers , enclosures that are basic elements in architecture . Therefore these elements embody sense of place as orientation , identification , identity. imageability, stabilitas loci, heirarchy. And these sensually compositional elements of poace concretize district, landmark, node, path, edge that ceate a setting into work and place in architecture & interior design.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1991.10a
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• pp.464-464
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• 1991

We address the problem of designing a physical CATV network with switched-star topology in which the broadband interactive service is provided. There are two types of decision variables: One is where to place conduit paths, and the other is how many cable units to be installed on each link traversed by an established conduit path. Due to the serious drawback of the conventional approach partitioning the problem into two subproblems, the unified approach handled in one setting is used here to attack the whole problem without dividing into two ones. In this paper, we present a mathematical design model and propose an efficient solution method exploiting the nice structure of it. In addition to this physical design, some results on logical network configuration have also been made. Finally, computaional experiments are conducted to illustrate the efficiency of our design approach.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.382-385
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• 2007

Constantly enhancing positioning accuracy by the Global Positioning System (GPS) technique is of great importance, but challenging, especially after the GPS positioning technique has been improved considerably during the past two decades. The associated main error sources have been reduced substantially, if not eliminated. Troposhpeic influence with its highly temporal and spatial variability appears to be one of the major error sources. It is hence an increased interest among GPS researchers to reduce the tropospheric influence or delay. Two techniques have been commonly implemented to correct the tropospheric impact. The first technique, known as parameter estimation, characterizes the path delay with empirical models and the parameters of interest are determined from the GPS measurements. The second strategy, termed as external correction, involves independent path delay measurements. The present study is an integration of both techniques in which the parameter estimation as well as external correction are used to correct the path delay for $110{\sim}210$ km range baselines. Twenty-four parameters have been obtained in 24 hours solution by setting the cutoff angle at 3 and 15 degrees for parameter estimation strategy. Measurements from meteorological instruments and water vapor radiometer (WVR) are applied in the GPS data processing, separately, as an external strategy of present research work. Interesting results have been found, indicating more stable repeatability in baseline when the external correction strategy is applied especially with the inclusion of WVR observations. The offset of an order of 1 cm is found in the baselines determined by the two strategies. On the other hand, parameter estimation exhibits more stable in terms of GPS height repeatability. The offset in the GPS height determined by the two strategies is on the order of few centimeters.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.11
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• pp.151-159
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• 2016

This paper proposes a ceramic heating element-based tankless instant electric water heater for hand/face washing that does not require a lot of hot water. The heating module, which heats the input water and outputs hot water, operates the ceramic heating element detecting input water using a flow sensor. Inside of the heating module is designed to form one flow path in order to get almost $15^{\circ}C$ increased heated water compared to the input water temperature within 2 second after 1.5 liter per minute water supply. The design validity is verified using a heat flow analysis of the water flow and temperature variations inside of the heating module also. Based on the design data, the heating module is constructed including a single rod-type ceramic heating element. After that, a prototype system having temperature setting function by three steps were constructed. The prototype system is connected to a 1.5 liter per minute water supply line, and the water output temperature and time measurement experiments confirmed that the proposed system output the heated water increased by $18.3^{\circ}C$ in case of third step setting within 2 second after water supply. And standby power is under 1 W and peak power does not exceed the permissible range for the general house usage. Several performance results verify that the proposed tankless instant electric water heater is applicable for the washstand of the house, highway rest area and factory so on as winter-time hand/face washing.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1133-1138
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• 2012

In the paper, design of nonlinear sliding surfaces which are based on optimal control is studied, The state trajectory by the input of optimal control was obtained by Frobenius theorem and matrix decomposition method, was set the nonlinear sliding surfaces of the system. The states is maintained to sliding surfaces from initial states. As the result, robustness of the system can be guaranteed throughout an entire response of the system starting form the initial time instance, the uncertainty and external disturbance that can occur during the reaching time is removed, the problem of large control input was solved, and setting the sliding surfaces optimal path was able to reduce the tracking time. The validity of the proposed control scheme is shown in computer simulation for inverted pendulum.

• Journal of the Korea Fashion and Costume Design Association
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• v.24 no.4
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• pp.87-99
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• 2022

The purpose of this study is to develop machine embroidery textile designs for each technique that can be expressed using a single-headed computer embroidery sewing machine through a machine embroidery CAD system. For research, embroidery CAD utilized the Artistic digitizer, and the guillotine computer-mechanical magnetization machine used ELNA. The design concept was limited to portraits and relics of independence activists in six memorial halls built in Korea. The results of this study are as follows. First, it was found that the machine embroidery texture, which could only be produced by industries in the past, can be expand in the infinite creative embroidery design area by enabling the digitalization of motif images and the simulation of machine embroidery techniques through various layout options. Second, in the development of machine embroidery textures, it was found that the setting of the width, height, axis ratio, stitch, object, path, length, density, layer order, etc. in embroidery CAD is a very important part of determining the completeness of the embroidery results. Third, mechanical embroidery textile designs, which can be represented by single-head computer machine embroidery machine were able to show colorful embroidery results that differs from the original image by using seven main techniques and five deep technique alone or in combination, according to the designer's intention.

• Journal of the Korea Society of Computer and Information
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• v.15 no.6
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• pp.65-72
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• 2010

In ad-hoc network, the technique to efficiently consume the limited amounts of energy is an important issue since the wireless terminal node is operated on batteries as their energy resource. In order to extend the system lifetime, through a balanced energy consumption, we must delay the situation in which a particular terminal node's energy is depleted and results in system disconnection. Also, the link, which has low reliability due to the mobility of the node, should be avoided considering the key element when setting up the route. The proposed CMLR method in this paper enables to increase the efficiency of energy consumption with a new cost function considering the residue energy of node, error rate of link, and transmission energy consumption. This method is extending the network lifetime and increasing the energy efficiency by compromising the value between the minimization of the transmission energy consumption and maximization of the node's lifetime. Through the simulations the proposed CMLR algorithm was verified by showing better performance over the conventional methods in terms of network lifetime and path efficiency.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.409-417
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• 2013

Mu-communication board supported by multi-communication is designed with Atxmega 128A1 which is a low power energy consuming of 8-bit microcontroller. ATxmega128A1 microcontroller consists of 8 UART(Universal asynchronous receiver/transmitter) ports which can be setting appropriate user interface having command line interpreter(CLI) program with each port, 2 kbytes EEPROM, 128 kbytes flash memory, 8 kbytes SRAM. 8 URAT ports are used for the multi communication modem, GPS module, etc. and EEPROM is used for saving a configuration for program running, and flash memory of 128 kbytes is used for storing a Firm Ware, and 8 kbytes SRAM is used for stack, storing memory of global variables while program running. If we uses the hybrid communication of path optimization of VHF, TRS and CDMA to remote control AtoN(aid to navigation), it is able to remove the communication shadow area. Even though there is a shadow area for individual communication method, we can select an optimum communication method. The compatibility of data has been enhanced as using of same data frame per communication devices. For the test, 8640 of data has been collected from the each buoy during 30 days in every 5 minutes and the receiving rate of the data has shown more than 99.4 %.

• Journal of the Korea Society of Computer and Information
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• v.12 no.3
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• pp.155-163
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• 2007

In this paper, Though sensors of Ubiquitous Middle-ware System based on RFID/USN can usually be reacted from six mouths to two years, they can be exhausted their power of storage battery only one day by communication rates and ranges. That is, the lifetime of sensor node is depended on how much spending power under wireless communication that can communicate its sensing data to its destination. Therefore, it is necessary that each sensor should be designed the Routing path to its destination, in order to remote collecting data. But, in order to improve lifetime of sensor node and modify inner setting, it is opposite to simple searching path method of sensor node by entering external commands. accordingly, 1:n sensor arrangement of n form command and data send-receive that is possible simulation do without interference other sensors and research to different sensor data analysis and conversion ways to convert Sensing data that accept from sensors to actuality information.