• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.211-211
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• 2012

The electrical loss of the photo-generated carriers is dominated by the recombination at the metal- semiconductor interface. In order to enhance the performance of the solar cells, many studies have been performed on the surface treatment with passivation layer like SiN, SiO2, Al2O3, and a-Si:H. In this work, Al2O3 thin films were investigated to reduce recombination at surface. The Al2O3 thin films have two advantages, such as good passivation properties and back surface field (BSF) effect at rear surface. It is usually deposited by atomic layer deposition (ALD) technique. However, ALD process is a very expensive process and it has rather low deposition rate. In this study, the ICP-assisted reactive magnetron sputtering method was used to deposit Al2O3 thin films. For optimization of the properties of the Al2O3 thin film, various fabrication conditions were controlled, such as ICP RF power, substrate bias voltage and deposition temperature, and argon to oxygen ratio. Chemical states and atomic concentration ratio were analyzed by x-ray photoelectron spectroscopy (XPS). In order to investigate the electrical properties, Al/(Al2O3 or SiO2,/Al2O3)/Si (MIS) devices were fabricated and characterized using the C-V measurement technique (HP 4284A). The detailed characteristics of the Al2O3 passivation thin films manufactured by ICP-assisted reactive magnetron sputtering technique will be shown and discussed.

• Journal of Powder Materials
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• v.22 no.6
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• pp.396-402
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• 2015

The organic binder-free paste for dye-sensitized solar cell (DSSC) has been investigated using peroxo titanium complex. The crystal structure of $TiO_2$ nanoparticles, morphology of $TiO_2$ film and electrical properties are analyzed by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Electrochemical Impedance Spectra (EIS), and solar simulator. The synthesized $TiO_2$ nanopowders by the peroxo titanium complex at 150, 300, $400^{\circ}C$, and $450^{\circ}C$ have anatase phase and average crystal sizes are calculated to be 4.2, 13.7, 16.9, and 20.9 nm, respectively. The DSSC prepared by the peroxo titanium complex binder have higher $V_{oc}$ and lower $J_{sc}$ values than that of the organic binder. It can be attributed to improvement of sintering properties of $TCO/TiO_2$ and $TiO_2/TiO_2$ interface and to formation of agglomerate by the nanoparticles. As a result, we have investigated the organic binder-free paste and 3.178% conversion efficiency of the DSSC at $450^{\circ}C$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.11
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• pp.2431-2436
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• 2012

This paper is implemented simple visible light communication system by combining the communications through LED lighting. It uses a variable PD sensor to the receiver and 1~12 the LED light-emitting device to the transmitter to realize LED visible light communication. Initial distance value of the developed transmission and receiver is more than 0~1.5m for LED visible light communication, the overall system transmission rate is organized with thousands kbps variability visible light media transmission system. It was measured the performance experiment during lens wearing or not wearing in order to increase the overall efficiency of the LED module, configures the LED and PD to existing PC module for the performance analysis of the implemented research, experiments the maximum communication distance of the transmitter/receiver according to LED count and the transmission rate, check about application methods and the possibility.

• Journal of the Korea Society of Computer and Information
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• v.10 no.1 s.33
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• pp.125-132
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• 2005

Visual programs consist of user interfaces and process logics. Because most visual IDEs(Integrated Development Environment) are utilized by only one developer, many developers can't cooperate simultaneously in one large-scaled visual Program to promote the development efficiency. This paper suggests a co-development environment for visual programs through which developers can cooperate with each other in the type of distribution. Developers can maintain the coincidence and the confidence of cooperation through a communication window and a job controller to process the Priority of the events that developers make in co-development work. Especially in large-sealed visual Program, the suggested environment reduces the burden that developer takes about the heavy development work, and many developers can divide and take the complex and large program modules according to their ability. We hope that the suggested environment can improve the development productivity and effectivity because it can reduce the time and effort for developing user interfaces in visual programs.

• Journal of the Optical Society of Korea
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• v.20 no.3
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• pp.389-395
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• 2016

A Carbon Fiber Composite (CFC) framework was designed for a small lightweight space camera. According to the distribution characteristics of each optical element in the optical system, CFC (M40J) was chosen to accomplish the design of the framework. TC4 embedded parts were used to solve the low accuracy of the CFC framework interface problem. An integrated optimization method and the optimization strategy which combined a genetic global optimization algorithm with a downhill simplex local optimization algorithm were adopted to optimize the structure parameters of the framework. After optimization, the total weight of the CFC framework and the TC4 embedded parts is 15.6 kg, accounting for only 18.4% that of the camera. The first order frequency of the camera reaches 104.8 Hz. Finally, a mechanical environment test was performed, and the result demonstrates that the first order frequency of the camera is 102 Hz, which is consistent with the simulation result. It further verifies the rationality and correctness of the optimization result. The integrated optimization method mentioned in this paper can be applied to the structure design of other space cameras, which can greatly improve the structure design efficiency.

• Journal of the Korea Society of Computer and Information
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• v.11 no.1 s.39
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• pp.259-271
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• 2006

In this paper, we propose relevant to design and implementation of an integrated management system for various speech corpora. The purpose of this paper is to manage an integrated management system for various kinds of speech corpora necessary for speech research and speech corpora constructed in different data formats. In addition, ways are considered to allow users to search with effect for speech corpora that meet various conditions which they want, and to allow them to add with ease corpora that are constructed newly. In order to achieve this goal, we design a global schema for an integrated management of new additional information without changing old speech corpora, and construct a web-based integrated management system based on the scheme that can be accessed without any temporal and spatial restrictions. Finally, we describe the web based interface which are the executed results involved in the service and show the efficiency of using the index view for implementation of integrated management system.

• Journal of the Korea Society of Computer and Information
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• v.15 no.4
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• pp.99-106
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• 2010

In this paper, we propose an industrial fluid monitoring system which performs the flow control function and monitors fluid pressure transmitted from MFC(Mass Flow Controller) unit. This system consists of MFC unit, channel device, and monitoring management software. MFC unit transmits the measured data of the fluid pressure to the channel device which would provide the input/output interface between management software, monitoring and MFC unit. The monitoring and management software control and analyze by monitoring real time measurements of fluid pressure from each channel of MFC unit. This software can process 20 channels and 0.1 monitoring cycle which gives 200 data measurement per second (i.e., 720,000 data/hour). At this time, the storage space increases in proportion to the rise of input data. This growth of data and storage space makes loss of data access efficiency. Therefore, it demands the implementation by sensing scheme of change scope and data, which can effectively manage the data.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.1
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• pp.271-281
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• 2005

The effects of radiation damping is used to compensate the truncated boundary which is relatively close to the structure-fluid interface in the fluid element surrounding the submerged structures. An efficient ring element is presented to model the shell and fluid element which fully utilizes the characteristics of the axisymmetry. The computational model uses the technique which separate the meridional shape and circumferential wave mode and gets similar result with the exact solution in the eigenvalues and the earthquake analysis. The fluid-structure interaction techniques is developed in the finite element analysis of two dimensional problems using the relations between pressure, nodal unknown acceleration and added mass assuming the fluid to be invicid, incompressible and irrotational. The effectiveness and efficiency of the technique is demonstrated by analyzing the free vibration and seismic analysis using the added mass matrix considering the structural deformation effect.

• The Journal of the Korea Contents Association
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• v.15 no.2
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• pp.40-57
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• 2015

IoT is the foundation technology that the things share the information through connected with Internet to provide service based on these information. It is applied to various fields such as personal, public and industry. Therefore, the service development is required to meet the requirement of the various service environments. The IoT service environment will be developed as the participation IoT service environment which increase the value and efficiency such as the Broadcasting and web services changed from the service provider environment to the user participation service. The user can directly reflect their requirements using the user participation IoT service environment. So, the types of IoT services will diverse and accelerate the spread of IoT service. In this paper, we derive the IoT service element through the analysis of various service scenarios, and propose the participation IoT service model and modeling mechanism. It provides the sequential service model and the relation based service model according to the service modeling proficiency of user. The proposed environment provides the web-based user interface that is implemented by the participation IoT service brokering platform.

• Journal of Korean Society of Archives and Records Management
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• v.16 no.3
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• pp.209-233
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• 2016

This study aims to propose a digital repository platform for academic department records in order to optimize the efficiency of collecting and utilizing academic department records in the absence of university archives and/or in circumstances of overlooking academic department records. First, the study conducted a survey on 70 staffs working in the departments of public and private universities as well as on 32 record managers in university archives about their awareness of and the situations related to academic department record management. Second, it designed the database and interface of a digital repository platform that registers and preserves academic department records effectively, and that proposes 26 essential metadata for managing academic department records. Third, this study built an academic department record repository named "Department Records Repository in the University (DRRU)" based on the OAK repository environment, with four core functions such as login, upload, search, and browse.