• Journal of Korea Technology Innovation Society
• /
• v.18 no.1
• /
• pp.98-125
• /
• 2015

This study will show the determinants of research productivity by fields in science and engineering. However, we present the differences between fields by personal attributes, research resources, and research productivities. The data includes 1,383 researchers who participated in the BK21 PLUS program during 2010-2012. The fields are physics, chemistry, biology, mechanics, electricity and electronics and chemical engineering. As for research productivity, 3 indices are used such as the number of papers publicized, patents and combination of papers and patents. As for explanation factors, two kinds of variables are used. The personal factors include sex, age, academic rank, location of affiliation, and country of PhD acquisition, and the resource factors are the number of graduate students, 3 types of research funds such as government fund, industrial fund and overseas fund. This study is unique in several aspects; Dealing with 3 productivity indices, and using massive official data, 6 different fields, and determinants of research productivity. The results are as follows; 1) there is a big difference in determinants by fields. 2) No variables affect the research productivity of all the fields at the same time. 3) In science, the number of determinants are quite low than engineering. 4) The ratio between papers and patents are different by fields. 5) The correlations between paper and patent by fields are different; no relationship in the field of physics and chemistry and positive relationship in the other 4 fields.

• KIISE Transactions on Computing Practices
• /
• v.23 no.6
• /
• pp.359-370
• /
• 2017

In overseas-hospital construction, the digital hospital is a trend that is based on the developments of the information and communication technologies, state-of-the-art medical equipment, smart health, and telemedicine. Along with the increasing proportion of IT, this has resulted in the spreading of the concept throughout city-like hospitals and their transformation into digital hospitals. In the hospital-construction business, IT is a key element that will link the modernization of the mechanical, electrical, and equipment systems, construction, and medical equipment for efficiency maximization through integration. The purpose of this study is the analysis of the market-expansion success factors through the construction of a success-story-based, IT-driven overseas-hospital business. The digital-hospital concept and the development process are analyzed through a literature review, and the success factors are analyzed in terms of the cost, time, and quality that are proposed in the project-management body of knowledge. The main contributions of this study regarding the success factors are as follows: First, a cost-side need exists regarding the establishment of strategic-value engineering in terms of increasing the value from the perspectives of the IT and operational infrastructures; second, in terms of the construction time, all of the hospital systems must comply with the established deadlines for the integrated test and commissioning; and lastly, in terms of quality, it is important to ensure that the System Integration digital-hospital services are delivered according to the user requirements.

• Polymer(Korea)
• /
• v.24 no.2
• /
• pp.268-275
• /
• 2000

We investigated the effect of polymer sublayer on volumetric resistivity and tensile strength of carbon fiber (CF)/polyethylene composite films fabricated under high intensity electric fields. The dependence of volumetric resistivity and tensile strength of the films on the polymer sublayer thickness or mass part exhibited complex behavior according to CF content and CF layer density in the films. As the thickness of polymer sublayer increases, two groups of processes at thermo-mechanical forming stage would take effects in the properties of the films. The first group comprises the increase of polymer layer thickness having reduced CF content compared with central or upper part of the film and insufficient wetting of CF resulting in the loosened structure near upper film side. The second group, on the other hand, is the improvement of mobility of molten sublayer leading to better distribution of CF throughout the film thickness and the formation of more compact structure. The different degree of contribution of these two competing processes at varied CF content and CF layer density could explain complex dependence of the film properties on the polymer sublayer. These results are important to optimize the electrical and mechanical properties of highly conductive polymer films, which can be used as electromagnetic interference shielding materials.

• Journal of the Korean Wood Science and Technology
• /
• v.44 no.3
• /
• pp.406-414
• /
• 2016

The lignin-based carbon nanofiber reinforced epoxy composite has been prepared by immersing carbon nanofiber mat in epoxy resin solution in order to evaluate the physical and mechanical properties. The thermal and mechanical properties of the carbon nanofiber reinforced epoxy composite were analyzed using thermogravimetric analysis (TGA), differential scanning calorimeter (DSC) and tensile tester. It was found that the thermal properties of the carbon nanofiber reinforced epoxy composite improved, with its glass-transition temperature ($T_g$) increased from $90.7^{\circ}C$ ($T_g$ of epoxy resin itself) to $106.9^{\circ}C$. The tensile strengths of carbon nanofiber mats made from both lignin-g-PAN copolymer and PAN were 7.2 MPa and 9.4 MPa, respectively. The resulting tensile strength of lignin-based carbon nanofiber reinforced epoxy composite became 43.0 MPa, the six times higher than that of lignin-based carbon nanofiber mats. The carbon nanofibers were pulled out after the tensile test of the carbon nanofiber reinforced epoxy composite due to high tensile strength (478.8 MPa) of an individual carbon nanofiber itself as well as low interfacial adhesion between fibers and matrices, confirmed by the SEM analysis.

• Journal of the Korean Vacuum Society
• /
• v.15 no.4
• /
• pp.331-337
• /
• 2006

Cavity-type beam position monitors were developed in collaboration with KEK to use for the future accelerators such as international linear collider (ILC) or x-ray free electron laser (XFEL) in PAL. BPM components such as BPM cavity, beam tubes, waveguides and feedthroughs were assembled by brazing at the same time to reduce mechanical errors during the fabrication. There are four screwed pins around outer rim of the cavity for the tuning of cavity frequency and x-y isolation. The resonance frequency of BPM is 6.422 GHz, the inner diameter of cavity is 53.822 mm, and the range of mechanical adjusting is $+ / - 250{\mu}m$. The x-y isolation was measured better than -40 dB after tuned. Test results of signal forms, x-y isolations, sensitivities are satisfied within requirements for the KEK ATF2 beam line.

• The Journal of the Acoustical Society of Korea
• /
• v.22 no.3
• /
• pp.217-223
• /
• 2003

A novel cooling method induced by acoustic streaming generated by ultrasonic vibration at 30㎑ is presented. Ultrasonic vibration is obtained by piezoelectric devices and the maximum vibration amplitude of 50 m is achieved by including a horn, mechanical vibration amplifier in the system and making the complete system resonate. To investigate the enhancement of heat transfer capability of acoustic streaming, the temperature variations of heat source and air in the vicinity of heat source are measured in real-time. It is observed that acoustic streaming is instantly induced by ultrasonic vibration, resulting in the significant temperature drop due to the bulk air flow caused by acoustic streaming. In addition, it is observed that the cooling effect on the heat source is maximized when the gap between the ultrasonic vibrator and heat source coincides with the multiples of half-wavelength of the ultrasonic wave. This fact results from the resonance of the sound wave. The theoretical analysis of the dependence on the gap is also accomplished and verified by experiment. The advantage of the proposed cooling method by acoustic streaming is noise-free due to the ultrasonic vibration and maintenance-free because of the absence of moving parts. Moreover. This cooling method can be utilized to the nano and micro-electro mechanical systems, where the fan-based conventional cooling method can not be employed.

• Journal of the Microelectronics and Packaging Society
• /
• v.18 no.4
• /
• pp.33-38
• /
• 2011

The p-type $(Bi_{0.2}Sb_{0.8})_2Te_3$ powers were fabricated by mechanical alloying and hot-pressed at temperatures of $350{\sim}550^{\circ}C$. Themoelectric properties of the hot-pressed $(Bi_{0.2}Sb_{0.8})_2Te_3$ were characterized as a function of the hot-pressing temperature. With increasing the hot-pressing temperature from $350^{\circ}C$ to $550^{\circ}C$, the Seebeck coefficient and the electrical resistivity decreased from 237 ${\mu}V/K$ to 210 ${\mu}V/K$ and 2.25 $m{\Omega}-cm$ to 1.34 $m{\Omega}-cm$, respectively. The power factor of the hot-pressed $(Bi_{0.2}Sb_{0.8})_2Te_3$ became larger from $24.95{\times}10^{-4}W/m-K^2$ to $32.85{\times}10^{-4}W/m-K^2$ with increasing the hot-pressing temperature from $350^{\circ}C$ to $550^{\circ}C$. Among the specimens hot-pressed at $350{\sim}550^{\circ}C$, the $(Bi_{0.2}Sb_{0.8})_2Te_3$ hot-pressed at $500^{\circ}C$ exhibited the maximum dimensionless figure-of-merit of 1.09 at $25^{\circ}C$ and 1.2 at $75^{\circ}C$.

• Journal of the Microelectronics and Packaging Society
• /
• v.12 no.3 s.36
• /
• pp.259-265
• /
• 2005

Characteristics of electroplated Ni films and $Ni-Al_2O_3$ composite films, such as yield strength, fracture elongation, and $Al_2O_3$ content, were evaluated as a function of electroplating current density. $Al_2O_3$ content was $11.48\~11.64\;vol\%$ for $Ni-Al_2O_3$ composite films electroplated at $5\~20\;mA/cm^2$, and decreased to $8.41\;vol\%$ at $30\;mA/cm^2$ $Ni-Al_2O_3$ possessed yield strengths higher than those of Ni films. Especially, $Ni-Al_2O_3$ fabricated at $5\;mA/cm^2$ exhibited $50\%$ improved yield strength. Fracture elongations of Ni and $Ni-Al_2O_3$ decreased with increasing the electroplating current density. $Ni-Al_2O_3$ electroplated at $5\;mA/cm^2$ exhibited more uniform dispersion of $Al_2O_3$ and higher yield strength and larger fracture elongation than the composite films processed at other current densities.

• Therapeutic Science for Rehabilitation
• /
• v.1 no.2
• /
• pp.5-13
• /
• 2012

The purpose of the research study is to confirm in effectiveness of somatosensory stimulation and to propose ideal training strategy for functional recovery of stroke patients. Through the previous literatures, our study investigated to the advantages and disadvantages in electrical somatosensory stimulation for stroke patients. Also, our study suggested to applicable strategies and confirmed to growth direction about new somatosensory stimulation therapy for functional recovery in stroke patients. Result of research study, although many study demonstrated to the effectiveness about somatosensory stimulation therapy for stroke patients, many therapists have experienced many difficulties in somatosensory stimulation application for stroke patients in rehabilitation environments. Thus, few have the therapeutic tools for somatosensory or specific sensory input. However, apparently the previous literatures showed that effectiveness of somatosensory stimulation on functional recovery of patients with brain damage. In conclusion, we can be confirmed that an ideal somatosensory stimulation program is very effective in promoting recovery and the integrity of the somatosensory pathway of stroke patients. Furthermore, we anticipate that using the customized mechanical interface provides to positive effects in rehabilitation of patients with brain damage.

• Journal of Internet Computing and Services
• /
• v.19 no.5
• /
• pp.21-31
• /
• 2018

Cyber penetration attacks can not only damage cyber space but can attack entire infrastructure such as electricity, gas, water, and nuclear power, which can cause enormous damage to the lives of the people. Also, cyber space has already been defined as the fifth battlefield, and strategic responses are very important. Most of recent cyber attacks are caused by malicious code, and since the number is more than 1.6 million per day, automated analysis technology to cope with a large amount of malicious code is very important. However, it is difficult to deal with malicious code encryption, obfuscation and packing, and the dynamic analysis technique is not limited to the performance requirements of dynamic analysis but also to the virtual There is a limit in coping with environment avoiding technology. In this paper, we propose a machine learning based malicious code analysis technique which improve the weakness of the detection performance of existing analysis technology while maintaining the light and high-speed analysis performance applicable to commercial endpoints. The results of this study show that 99.13% accuracy, 99.26% precision and 99.09% recall analysis performance of 71,000 normal file and malicious code in commercial environment and analysis time in PC environment can be analyzed more than 5 per second, and it can be operated independently in the endpoint environment and it is considered that it works in complementary form in operation in conjunction with existing antivirus technology and static and dynamic analysis technology. It is also expected to be used as a core element of EDR technology and malware variant analysis.