• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.14 no.1
• /
• pp.8-14
• /
• 2005

The purposes of using cutting fluid during cutting have been cooling, lubricating, chip washing, and anti-corroding. However, the present manufacturing industry restricts the use of cutting fluid because cutting fluid contains poisonous substances which are harmful to the human body. Therefore dry cutting becomes an unavoidable assignment and a lot of researches have studied cutting methods without using cutting fluid. Because dry turning is a continuous work, tools life is reduced by continuous heat generation and surface gets rough due to reduced lubrication, so it is important to consider these situations. In this paper, the way of selecting the optimal machining condition by the minimum number of experiments and the effectiveness of using compressed air in high hardness materials through Taguchi method have been found. Dry cutting using compressed air showed better cutting characteristics than normal dry cutting with respect to by cutting force, tool wear, and surface roughness. Also, the optimal machining condition f3r dry cutting using compressed air could be selected through Taguchi method.

• Journal of the Korean Vacuum Society
• /
• v.12 no.S1
• /
• pp.70-73
• /
• 2003

Sum-frequency vibrational spectroscopy has recently been used to investigate the surface of the various polymers and was able to find the chemical compositions and structures specific to the surface. Here we report our studies on two specific polymer samples to demonstrate its capability. Polyimide thin films were made by spin coating on fused quartz and $CaF_2$ substrates. The sum-frequency signal originating mainly from the air/polymer interface showed markedly different spectra, indicating the structural change of the polymer surface depending on the underlying substrate. Various polyethylene surfaces were also investigated by sum-frequency vibrational spectroscopy. The surface of polyethylene samples in the CH-region showed different sum-frequency spectra, presumably due to the trace amount of additives having much higher concentration at the air/polymer interface. These examples demonstrate the surface and interface of the polymer could have different structure and chemical composition from those of a bulk, which can be studied effectively by surface nonlinear optical spectroscopy.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.15 no.6
• /
• pp.658-663
• /
• 2015

In the previous work, we have proposed an integrate-and-fire neuron circuit and synaptic device based on the floating body MOSFET [1-3]. Integrate-and-Fire(I&F) neuron circuit emulates the biological neuron characteristics such as integration, threshold triggering, output generation, refractory period using floating body MOSFET. The synaptic device has short-term and long-term memory in a single silicon device. In this paper, we connect the neuron circuit and the synaptic device using current mirror circuit for summation of post synaptic pulses. We emulate spike-timing-dependent-plasticity (STDP) characteristics of the synapse using feedback voltage without controller or clock. Using memory device in the logic circuit, we can emulate biological synapse and neuron with a small number of devices.

• Journal of the Korean Society of Costume
• /
• v.51 no.6
• /
• pp.85-99
• /
• 2001

본 연구에서는 유니섹스 영 캐주얼웨어의 국내브랜드를 중심으로 고찰한 후 그 디자인 특성에 대해 살펴보고 한 시대의 패션현상을 규명하고자 하는데 그 목적이 있다. 연구방법은 국내 패션시장의 유니섹스 영 캐주얼웨어에 대한 디자인 특성을 살펴보기 위해 신세대의 하위문화와 국내브랜드 시장조사를 통한 유니섹스 영 캐주얼웨어의 동향에 대한 일반적 고찰을 한 후 영 캐주얼웨어의 브랜드를 디자인의 차이에 따라 분류하고, 그 디자인 특성을 컬러, 소재, 스타일, 아이템별로 구분하여 분석하였다. '00 S/S, '00 F/W의 유니섹스 영 캐주얼웨어 브랜드를 중심으로 고찰해 보고자 패션 정보잡지와 인터넷의 패션사이트를 검색하였다. 유니섹스 영 캐주얼웨어의 브랜드별 시장조사를 통한 그 결과는 다음과 같다. 1. 영상매체, 대중음악. 스포츠, 스타문화로 나타난 신세대의 하위문화는 탈중심성, 탈국경화, 의미의 해체 등의 포스트모던적 문화현상이며. 유니섹스 영 캐주얼웨어는 자유와 개성을 추구하는 신세대의 라이프 스타일을 잘 반영한 하위문화의 복식양식으로서 현대 패션에 영향을 미치고 있다. 2. 기성복업체는 신세대가 가지고 있는 새로운 욕구와 감성을 겨냥한 브랜드를 개발하고 판매촉진을 위해 전력을 다하는 과정에서 신세대의 하위문화를 반영한 유니섹스 영 캐주얼웨어의 일반적인 복식양식을 형성하였다. 3. 국내시장의 유니섹스 영 캐주얼웨어는 디자인 특성에 따라 컴포터블 캐주얼웨어, 스포츠 캐주얼웨어, 힙합 캐주얼웨어로 구분된다.

• Korean Journal of Animal Reproduction
• /
• v.26 no.4
• /
• pp.321-328
• /
• 2002

The hormone resistin is associated with type II diabetes mellitus in rodent model. Resistin impairs glucose tolerance and insulin action. A new class of anti-diabetic drugs were called thiazolidinediones (TZDs) downreguates a resistin. Resistin gene expression is induced during adipocyte differentiation and resistin polypeptide is secreted by adipocytes. But, the correlation between increased adiposity and resistin remains unknown. The objectives of this study was to clone a mouse resistin CDNA and to generate transgenic mice overexpressing mouse resistin gene. The pCMV-mus/resistin gene was prepared from previous recombinant pTargeT$^{TM}$-mus/resistin by digestion of Bgl II, and has used for microin- jection into pronuclei of one cell embryos. Mouse resistin expression was detected in transgenic F$_1$mice by RT-PCR. The transgenic mouse with resistin gene expression has heavier body weight which was measured higher level of plasma glucose than that of normal mouse. And in diet-induced experiments, in fasting group, resistin expression was higher than that of re-feeding group. This result demonstrates that the resistin gene overexpressing mice may be became to obesity and be useful as an animal disease model to be diabetes caused by insulin resistance of resistin.n.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.1
• /
• pp.321-344
• /
• 2017

Smart homes are the new generation of homes where pervasive computing is employed to make the lives of the residents more convenient. Human activity recognition (HAR) is a fundamental task in these environments. Since critical decisions will be made based on HAR results, accurate recognition of human activities with low uncertainty is of crucial importance. In this paper, a novel HAR method based on a difference of convex programming (DCP) problem is represented, which manages to handle uncertainty. For this purpose, given an input sensor data stream, a primary belief in each activity is calculated for the sensor events. Since the primary beliefs are calculated based on some abstractions, they naturally bear an amount of uncertainty. To mitigate the effect of the uncertainty, a DCP problem is defined and solved to yield secondary beliefs. In this procedure, the uncertainty stemming from a sensor event is alleviated by its neighboring sensor events in the input stream. The final activity inference is based on the secondary beliefs. The proposed method is evaluated using a well-known and publicly available dataset. It is compared to four HAR schemes, which are based on temporal probabilistic graphical models, and a convex optimization-based HAR procedure, as benchmarks. The proposed method outperforms the benchmarks, having an acceptable accuracy of 82.61%, and an average F-measure of 82.3%.

• Journal of Internet Computing and Services
• /
• v.21 no.5
• /
• pp.57-65
• /
• 2020

At present, the existing virus recognition systems usually use signature approach to detect malicious executable files, but these methods often fail to detect new and invisible malware. At the same time, some methods try to use more general features to detect malware, and achieve some success. Moreover, machine learning-based approaches are applied to detect malware, which depend on features extracted from malicious codes. However, the different distribution of features oftraining and testing datasets also impacts the effectiveness of the detection models. And the generation oflabeled datasets need to spend a significant amount time, which degrades the performance of the learning method. In this paper, we use transfer learning to detect new and previously unseen malware. We first extract the features of Portable Executable (PE) files, then combine transfer learning training model with KNN approachto detect the new and unseen malware. We also evaluate the detection performance of a classifier in terms of precision, recall, F1, and so on. The experimental results demonstrate that proposed method with high detection rates andcan be anticipated to carry out as well in the real-world environment.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.05d
• /
• pp.101-106
• /
• 1996

For the application of the neutron flux mapping, an accurate calculation of the sensitivity is required because the sensitivity is proportional to the neutron flux density. Sensitivity is defined as the current per unit length per unit neutron flux and it mainly depends on the depression factor(f), the escape probability from the emitter($\varepsilon$1) and the charge build-up factor of the insulator layer(c). A Monte Carlo simulation was accomplished to calculate the sensitivity of rhodium emitter material and alumina(Al$_2$O$_3$) insulator with a cylindrical geometry, based on the (n,${\beta}$) interaction and on other interaction including the secondary electron generation for the more accurate estimation of the sensitivity. From the simulation results, factors fur the sensitivity were accurately calculated and compared with other theoretical and experimental values. In addition, the sensitivity linearly increases and saturates as the emitter radius increases. The accomplished method is useful in the analysis for the change of SPND sensitivity as a function of burn-up and in the optimum design of SPND.

• Journal of ILASS-Korea
• /
• v.22 no.2
• /
• pp.80-86
• /
• 2017

The soot formation characteristics of various alkane-based single fuel droplets were studied in this work. Also, This study was performed to provide the database of the soot behavior and formation of alkane-based single fuel droplet. The experimental conditions were set to 1.0 atm of ambient pressure ($P_{amb}$), 21% of oxygen concentration ($O_2$) and 79% of nitrogen concentration ($N_2$). Combustion and soot formation of single fuel droplet was visualized by visualization system with high speed camera. At the same time, ambient pressure, oxygen concentration and nitrogen concentration were maintained by ambient condition control system. Soot formation characteristics was analyzed and compared on the basis of intensity ratio ($I/I_0$) of background image. The results of toluene fuel droplet showed the largest soot generation. Soot volume fraction ($f_v$) was almost the same under the identical fuel types regardless of various initial droplet diameter ($d_0$) since thermophoretic flux was not much changed under the same ambient conditions.

• Journal of Aquaculture
• /
• v.10 no.1
• /
• pp.33-37
• /
• 1997

construct containing reporter gene(pFV4CAT) regulated by carp $\beta$-actin promoter was microinjected into the one-cell stage egg of mud loach (Misgurnus mizolepis), and was successfully expressed, possibly by the integration into the genome. Both mean hatching success and early survival of the microinjected groups were not significantly different with those of control groups (P>0.05). The incidence of transgene was ranged from 7 to 48% based on the PCR and/or Southern blot analyses with the DNA prepared from fin or blood tissue. The spatial and temporal patterns of expression of the pFV4CAT gene, measured by in situ immunohistochemical analysis peroxidase-conjugated anti-CAT antibody, were variable among the experimental individuals. These results suggest that carp $\beta$-actin promoter is effective to express other transgene in mud loach, such that this promoter can be useful in the generation of valuable transgenic mud loach.