• Biomedical Engineering Letters
• /
• v.8 no.4
• /
• pp.337-344
• /
• 2018

Additive manufacturing (AM) is an alternative metal fabrication technology. The outstanding advantage of AM (3D-printing, direct manufacturing), is the ability to form shapes that cannot be formed with any other traditional technology. 3D-printing began as a new method of prototyping in plastics. Nowadays, AM in metals allows to realize not only net-shape geometry, but also high fatigue strength and corrosion resistant parts. This success of AM in metals enables new applications of the technology in important fields, such as production of medical implants. The 3D-printing of medical implants is an extremely rapidly developing application. The success of this development lies in the fact that patient-specific implants can promote patient recovery, as often it is the only alternative to amputation. The production of AM implants provides a relatively fast and effective solution for complex surgical cases. However, there are still numerous challenging open issues in medical 3D-printing. The goal of the current research review is to explain the whole technological and design chain of bio-medical bone implant production from the computed tomography that is performed by the surgeon, to conversion to a computer aided drawing file, to production of implants, including the necessary post-processing procedures and certification. The current work presents examples that were produced by joint work of Polygon Medical Engineering, Russia and by TechMed, the AM Center of Israel Institute of Metals. Polygon provided 3D-planning and 3D-modelling specifically for the implants production. TechMed were in charge of the optimization of models and they manufactured the implants by Electron-Beam Melting ($EBM^{(R)}$), using an Arcam $EBM^{(R)}$ A2X machine.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2007.11a
• /
• pp.255-260
• /
• 2007

The construction industry has been recognized as lagging behind other industries in the area of research and development (R&D) due primarily to the lack of R&D funds. To overcome this situation, the Korea Ministry of Construction and Transportation has a plan to expand its investments on the construction R&D up to 1.72 billion US dollars over the next 3 years. Despite this effort, it is still challenging to conduct the quantitative measurement on the efficiency of construction R&D projects, which can be utilized as the objective basis in the reasonable selection of a promising R&D team or in the consequential evaluation of a R&D performance. This study aims to conduct the efficiency analysis on the construction R&D projects to provide the basis for evaluating the performance of research and development. Toward this end, this study performs an efficiency analysis, which reflects all of the input and output data into/from the construction R&D by utilizing the Data Envelopment Analysis (DEA). The proposed methodology can be utilized to make a better decision on the priority of the R&D investments and present a sound basis to suggest the areas to be improved so as to reduce the inefficiency of R&D projects.

• Aerospace Engineering and Technology
• /
• v.7 no.2
• /
• pp.38-45
• /
• 2008

It is challenging to build the integrated information system for a large scale cooperative R & D project. To develop the aircraft program which especially has several leading agencies and is supported by many demestic/foreign participating companies, the common data flow in harmony is the core factor to achieve a development goal. For this, the development are carried out maintaining the existing management systems of agencies and companies. As a first step, the standard for the common data information and the classification category of technical data are defined. Second, the work flow standards are also set. Based on the foundation, the efficient technical data management system are built including the function of storage, inquiry, revision, link, approval, submission, etc.

• Journal of Information Technology Services
• /
• v.10 no.1
• /
• pp.151-165
• /
• 2011

Recently building up of u-learning oriented teaching and learning system has been expanded rapidly, However domestic junior college's challenging for adapting it might be slower than other educational body's doing, and in that result it might be paid more or be taken longer time to improve their old system effectively. Now, it is very time for them to develop and implement u-learning oriented teaching and learning system quickly. This paper offers and draws the core factors to design ubiquitous teaching and learning model systematically through investigation of worldwide recent technology and R&D, patent, service and standardization tendency related with u-learnig modeling.

• IEIE Transactions on Smart Processing and Computing
• /
• v.4 no.4
• /
• pp.258-264
• /
• 2015

The first 77 GHz transceiver that applies a heterodyne structure-based linear frequency modulation-frequency shift keying (LFM-FSK) front-end module (FEM) is presented. An LFM-FSK waveform generator is proposed for the transceiver design to avoid ghost target detection in a multi-target environment. This FEM consists of three parts: a frequency synthesizer, a 77 GHz up/down converter, and a baseband block. The purpose of the FEM is to make an appropriate beat frequency, which will be the key to solving problems in the digital signal processor (DSP). This paper mainly focuses on the most challenging tasks, including generating and conveying the correct transmission waveform in the 77 GHz frequency band to the DSP. A synthesizer test confirmed that the developed module for the signal generator of the LFM-FSK can produce an adequate transmission signal. Additionally, a loop back test confirmed that the output frequency of this module works well. This development will contribute to future progress in integrating a radar module for multi-target detection. By using the LFM-FSK waveform method, this radar transceiver is expected to provide multi-target detection, in contrast to the existing method.

• Journal of the Korean Institute of Gas
• /
• v.19 no.5
• /
• pp.104-111
• /
• 2015

The technology development of pipeline transportation of natural gas at artic and northern ice environments should be considered with unique characteristics of permafrost territory as a very interesting and challenging area. This work is to investigate bottleneck techniques and major impact factors through a literature search to figure out the core technology of the transport pipeline. Especially, theoretical approach themes could be determined to develop the technology flow assurance for permafrost regions through documentary survey on the considerations of thermo-fluid. Also, basic results through theoretical approaches could be achieved.

• Nuclear Engineering and Technology
• /
• v.55 no.6
• /
• pp.2034-2046
• /
• 2023

Industrial control systems in nuclear facilities are facing increasing cyber threats due to the widespread use of information and communication equipment. To implement cyber security programs effectively through the RG 5.71, it is necessary to quantitatively assess cyber risks. However, this can be challenging due to limited historical data on threats and customized Critical Digital Assets (CDAs) in nuclear facilities. Previous works have focused on identifying data flows, the assets where the data is stored and processed, which means that the methods are heavily biased towards information security concerns. Additionally, in nuclear facilities, cyber threats need to be analyzed from a safety perspective. In this study, we use the system theoretic process analysis to identify system-level threat scenarios that could violate safety constraints. Instead of quantifying the likelihood of exploiting vulnerabilities, we quantify Security Control Measures (SCMs) against the identified threat scenarios. We classify the system and CDAs into four consequence-based classes, as presented in NEI 13-10, to analyze the adversary impact on CDAs. This allows for the ranking of identified threat scenarios according to the quantified SCMs. The proposed framework enables stakeholders to more effectively and accurately rank cyber risks, as well as establish security and response strategies.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2004.02a
• /
• pp.143-149
• /
• 2004

China is facing the challenging problems in both the potential energy resource shortage and the serious environmental pollutions. The author suggests that nuclear energy could play an important role for ensuring the long term energy security in China. The technical problems to be solved for the sustainable development of nuclear energy in China are also discussed and the R&D work in next 20 years are briefly suggested to meet the requirements of nuclear energy development in China.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.25 no.3
• /
• pp.221-243
• /
• 2023

The use of roadheaders has been increasing to mitigate the problems of noise and vibration during tunneling operations in urban area. Since lack of experience of roadheader for hard rock, the selection of appropriate machines and the evaluation of cutting rates have been challenging. Currently, empirical models developed overseas are commonly used to evaluate cutting rates, but their effectiveness has not been verified for domestic rocks. In this paper, a comprehensive literature review was conducted to assess the rock cutting force, cutterhead capacity, and cutting rate to select the appropriate machine and evaluate its performance. The cutterhead capacity was reviewed based on the literature results for the site. Furthermore, a new empirical model and simplified method for predicting cutting rates were proposed through data analysis in relation to operation time and rock strength, and compared with those of the conventional model from the manufacturer. The results show good agreement for high strength range upper 80 MPa of uniaxial compressive strength.

• Structural Engineering and Mechanics
• /
• v.84 no.6
• /
• pp.723-731
• /
• 2022

Functionally graded materials (FGMs) have been spotlighted as an advanced composite material, accordingly the intensive studies have focused on FGMs to examine their mechanical behaviors. Among them is thermal buckling which has been a challenging subject, because its behavior is connected directly to the safety of structural system. In this context, this paper presents the numerical analysis of thermal buckling of metal-ceramic functionally graded (FG) plates. For an accurate and effective buckling analysis, a new numerical method is developed by making use of (1,1,0) hierarchical model and 2-D natural element method (NEM). Based on 3-D elasticity theory, the displacement field is expressed by a product of 1-D assumed thickness monomials and 2-D in-plane functions which are approximated by NEM. The numerical method is compared with the reference solutions through the benchmark test, from which its numerical accuracy has been verified. Using the developed numerical method, the critical buckling temperatures of metal-ceramic FG plates are parametrically investigated with respect to the major design parameters.