• Nuclear Engineering and Technology
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• 제41권1호
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• pp.1-10
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• 2009

The safe and reliable performance of fusion and fission plants depends on the choice of suitable materials and an assessment of long-term materials degradation. These materials are degraded by their exposure to extreme conditions; it is necessary, therefore, to address the issue of long-term damage evolution of materials under service exposure in advanced plants. The empirical approach to the study of structural materials and fuels is reaching its limit when used to define and extrapolate new materials, new environments, or new operating conditions due to a lack of knowledge of the basic principles and mechanisms present. Materials designed for future Gen IV systems require significant innovation for the new environments that the materials will be exposed to. Thus, it is a challenge to understand the materials more precisely and to go far beyond the current empirical design methodology. Breakthrough technology is being achieved with the incorporation in design codes of a fundamental understanding of the properties of materials. This paper discusses the multi-scale, multi-code computations and multi-dimensional modelling undertaken to understand the mechanical properties of these materials. Such an approach is envisaged to probe beyond currently possible approaches to become a predictive tool in estimating the mechanical properties and lifetimes of materials.

• Journal of the Optical Society of Korea
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• 제13권2호
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• pp.193-200
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• 2009

A compact imaging spectrometer (COMIS) is currently under development for use in the STSAT3 microsatellite. COMIS images the Earth's surface and atmosphere with ground sampling distances of ${\sim}30m$ in the $18{\sim}62$ spectral bands ($4.0{\sim}1.05{\mu}m$) for the nadir looking at an altitude of 700 km. COMIS has an imaging telescope and an imaging spectrometer box into which three electronics PCBs are embedded. These are designed into a single assembly with dimensions of 35(L) $\times$ 20(W) $\times$ 12(H) $cm^3$ and a mass of 4.3 kg. Optomechanical design efforts are focused on manufacturing ease, alignment, assembly, testing and improved robustness in space environments. Finite element analysis demonstrates that COMIS will survive in launch and space environments and perform the system modulation transfer function (MTF) in excess of 0.29 at the Nyquist frequency of the CCD detector (38.5 lines-per-mm).

• Korean Institute of Interior Design Journal
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• 제20권5호
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• pp.245-253
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• 2011

As interests towards health rapidly increase recently, interests and demand for hospital interior space are increasing as well. Therefore, most of today's hospitals that have been functionally designed are transforming into healing environments that consider psychological aspects, in order to assist patients forget about fear, desperation and have peace of mind. With such creation method of healing environment, natural elements can be applied to spaces in order to allow patients feel vitality, hope and adapt positive thinking, and these can eventually lead to affluent fusion of humans, nature and space. Through case analyses of how natural elements are applied to hospital's interior space, this study understands its characteristics. According to the findings, nature is largely classified into light, water, plant, stone/soil, and its application methods can be classified into center, transition, continuity, division, opening and closure. As evident from case analyses, application of natural elements to hospital's interior space promotes exchanges among patients through community formation, and achieves the effect of spatial concentration and public place. Also, ambiguity of exterior and interior boundary creates a sense of expansion and continuous effect, and can also provide a healing environment that can fully absorb natural environment open to patients. This study aims to be of service when designing hospital's interior space, with its natural element application method for healing environment research, and wishes for continuous studies on healing environments with more diverse methods.

• Journal of Korea Multimedia Society
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• 제9권3호
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• pp.342-352
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• 2006

Nowadays, Computing environment is changing to ubiquitous. In such ubiquitous computing environments, entities expect to access resources and services at any time from anywhere. Therefore, tile wily how to establish trust relationship among previously unknown devices or resources is needed under such environments. In this paper, we firstly review a model to delegate the trust to communicating entities in ubiquitous environment and its security problems(e.g., malicious right-delegation and revocation of right-delegation). Then, we design a new model for secure delegation over communication entities which is based on two-party signature scheme, and implement it.

• Journal of Institute of Control, Robotics and Systems
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• 제16권2호
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• pp.126-133
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• 2010

Due to the deployment of various wireless networks originating from CDMA, GSM, and WLAN, it became very convenient to exchange information from one place to another. As compared with the traditional environments for one-way information distribution based on fixed radio frequency bands, the convenient wireless network environments will bring about many changes in positioning technologies based on global navigation satellites. Among the many changes to come, the reconfigurable receiver network is one of the most attractive concepts since it can be tailored to a specific application area among networked robots, formation flying, bridge monitoring, and traffic monitoring. As an initial study to develop a reconfigurable receiver network, this paper deals with the design and implementation of the key elements of the reconfigurable receiver netowork; server, broadcaster, and client. In the designed receiver network, a sever receives and decodes measurements from a reference receiver installed at a known location, a broadcaster processes and transfers the messages from servers to clients and manages connections with servers and clients, a client receives the messages from the broadcaster and performs differential positioning. A real-time experiment result is demonstrated to validate the functionalities of each network element.

• The Transactions of the Korea Information Processing Society
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• 제7권10호
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• pp.3148-3154
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• 2000

In this paper. the design and implementationof the on-line registration system for the school affairs is described. The environments for the system configurations include a PC server under Linux Iperating System. Apache Web-server, and MySQL as database engine. In addition, PHP, which becomes a popular Internet server-based script language lately, is used to implement a real-time database. In order to avoid overload problems during short-term registration period, which deconstraces the typical surge of traffics, the proposed system is designed to minimize the unnecessary interfacing tasks. On administrator side task, the sytem is designed to have environments by separating the dechcated server that restricts the scope of specific database thasks. In doing so, it become possibal to build an optical system by distributing, balancing the transaction load, maintainimg the security and efficient administrative tasks.

• Korean Institute of Interior Design Journal
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• 제37호
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• pp.39-47
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• 2003

The purpose of this paper was to analyze and to compare the creativity of Nam-June Paik and Louis 1. Kahn to understand the characteristics of creative people. Both of them got strong supports from their family and close people. As they were not originally from the U.S., political and city environments where they settled in the U.S. for the first time strongly influenced their creative activity. The difference in the creative contexts of Paik and Kahn is that Paik had more visual cues in his childhood due to the rich environments. The various visual cues influenced his wide interests in video arts. In creative process, even though both of them more focused on the beginning stage of creative process, there were differences in creative problem solving styles. Kahn considered the imaging and perception as the most Important working process. For him, intuition(gestalt view) and ideation(generator) are more important than intellectual skill. On the other hand, Paik thought the symbolization(conceptualizer) based on his own experience and philosophy(associationism) was the most important.

• Progress in Superconductivity and Cryogenics
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• 제24권1호
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• pp.8-12
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• 2022

Recently, research on applying composite materials to various industrial fields is being actively conducted. In particular, composite materials fabricated by Fused Deposition Modeling 3D printers have more advantages than existing materials as they have fewer restrictions on manufacturing shape, reduce the time required, weight. With these advantages, it is possible to consider utilizing composite materials in cryogenic environments such as the application of liquid oxygen and liquid hydrogen, which are mainly used in an aerospace and mobility. However, FDM composite materials are not verified in cryogenic environments less than 150K. This study evaluates the characteristics of composite materials such as tensile strength and strain using a UTM (Universal Testing Machine). The specimen is immersed in liquid nitrogen (77 K) to cool down during the test. The specimen is fabricated using 3D print, and can be manufactured by stacking reinforced fibers such as carbon fiber, fiber glass, and aramid fiber (Kevlar) with base material (Onyx). For the experimental method and specimen shape, international standards ASTM D638 and ASTM D3039 for tensile testing of composite materials were referenced.

• Journal of Korea Society of Industrial Information Systems
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• 제14권4호
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• pp.65-74
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• 2009

The risk of health impairment due to poor ventilation, fire and explosion by inflammable materials, and other unintended occurrences is always present in dangerous workplaces such as manholes, underground septic tanks, storage tanks and confined areas. Therefore, it a system which can monitor harmful working environment through sensors in workplace on a realtime basis and keep workers safe from the risk is needed. This paper has attempted to design an inference engine to monitor harmful environments in the workplace. The proposed inference engine has a rule-based system structure using JESS. This system is not confined to a particular computing platform and is easily interlocked with OSGi-based middleware.

• Korean Journal of Construction Engineering and Management
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• 제24권5호
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• pp.73-82
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• 2023

Optimization of Construction Site Layout Planning (CSLP) heavily relies on workers' travel paths. However, traditional path generation approaches predominantly focus on the shortest path, often neglecting critical variables such as individual wayfinding tendencies, the spatial arrangement of site objects, and potential hazards. These oversights can lead to compromised path simulations, resulting in less reliable site layout plans. While Deep Reinforcement Learning (DRL) has been proposed as a potential alternative to address these issues, it has shown limitations. Despite presenting more realistic travel paths by considering these variables, DRL often struggles with efficiency in complex environments, leading to extended learning times and potential failures. To overcome these challenges, this study introduces a refined model that enhances spatial navigation capabilities and learning performance by integrating workers' visibility into the reward functions. The proposed model demonstrated a 12.47% increase in the pathfinding success rate and notable improvements in the other two performance measures compared to the existing DRL framework. The adoption of this model could greatly enhance the reliability of the results, ultimately improving site operational efficiency and safety management such as by reducing site congestion and accidents. Future research could expand this study by simulating travel paths in dynamic, multi-agent environments that represent different stages of construction.