• Journal of Broadcast Engineering
• /
• v.8 no.4
• /
• pp.325-338
• /
• 2003

Video adaptation in response to dynamic resource conditions and user preferences is required as a key technology to enable universal multimedia access (UMA) through heterogeneous networks by a multitude of devices In a seamless way. Although many adaptation techniques exist, selections of appropriate adaptations among multiple choices that would satisfy given constraints are often ad hoc. To provide a systematic solution, we present a general conceptual framework to model video entity, adaptation, resource, utility, and relations among them. It allows for formulation of various adaptation problems as resource-constrained utility maximization. We apply the framework to a practical case of dynamic bit rate adaptation of MPEG-4 video streams by employing combination of frame dropping and DCT coefficient dropping. Furthermore, we present a descriptor, which has been accepted as a part of MPEG-21 Digital Item Adaptation (DIA), for supporting terminal and network quality of service (QoS) in an interoperable manner. Experiments are presented to demonstrate the feasibility of the presented framework using the descriptor.

• Journal of Life Science
• /
• v.29 no.11
• /
• pp.1179-1191
• /
• 2019

Cancer cells undergo the epithelial-mesenchymal transition (EMT) and show unique oncogenic metabolic phenotypes such as the glycolytic switch (Warburg effect) which are important for tumor development and progression. The EMT is a critical process for tumor invasion and metastasis. High-mobility group box 1 (HMGB1) is a chromatin-associated nuclear protein, but it acts as a damage-associated molecular pattern molecule when released from dying cells and immune cells. HMGB1 induces the EMT, as well as invasion and metastasis, thereby contributing to tumor progression. Here, we show that HMGB1 induced the EMT by activating Snail. In addition, the HMGB1/Snail cascade was found induce a glycolytic switch. HMGB1 also suppressed mitochondrial respiration and cytochrome c oxidase (COX) activity by a Snail-dependent reduction in the expression of the COX subunits COXVIIa and COXVIIc. HMGB1 also upregulated the expression of several key glycolytic enzymes, including hexokinase 2 (HK2), phosphofructokinase-2/fructose-2,6-bisphosphatase 2 (PFKFB2), and phosphoglycerate mutase 1 (PGAM1), in a Snail-dependent manner. However, HMGB1 was found to regulate some other glycolytic enzymes including lactate dehydrogenases A and B (LDHA and LDHB), glucose transporter 1 (GLUT1), and monocarboxylate transporters 1 and 4 (MCT1 and 4) in a Snail-independent manner. Transfection with short hairpin RNAs against HK2, PFKFB2, and PGAM1 prevented the HMGB1-induced EMT, indicating that glycolysis is associated with HMGB1-induced EMT. These findings demonstrate that HMGB1 signaling induces the EMT, glycolytic switch, and mitochondrial repression via Snail activation.

• Korean Chemical Engineering Research
• /
• v.54 no.1
• /
• pp.114-119
• /
• 2016

In this study, we tried to add the conductivity to natural polymer like bacterial cellulose (BC) coated with the conductive polymer PEDOT:PEG, graphene and silver nano-wire (AgNW). Sulfuric acid of 10 to 20% was previously mixed with PEDOT:PEG and then the solution was electron spin-coated on the BC membrane. And then, additive coating with graphene and AgNW were done to improve conductivity, which was examined by hall effect. As the result, we confirmed a considerable improvement of conductivity compared to BC-coated film without sulfuric acid treatment as $2.487{\times}10^{10}$ vs $8.093{\times}10^{15}$ ($1/cm^3$), showing higher electron density with $3.25{\times}10^5$ times. Also, we identified that changed particle type to the polymer type by sulfuric acid using SEM analysis. For FT-IR analysis, it was confirmed that S-O radical ($1200cm^{-1}$) increased in the sulfuric acid treatment than non-treated sulfuric acid. As the method used very small amount of PEDOT:PEG, its transparency could be kept, and pre-treatment process of sulfuric acid will be able to simplify the production process.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.10
• /
• pp.14-22
• /
• 2010

The source/channel/drain regions are formed by ion implantation with different dopant types of $n^+/p^{(+)}/n^+$ in the fabrication of the conventional n-type metal-oxide-semiconductor field effect transistor(NMOSFET). In implementing the ultra-small devices with channel length of sub-30 nm, in order to achieve the designed effective channel length accurately, low thermal budget should be considered in the fabrication processes for minimizing the lateral diffusion of dopants although the implanted ions should be activated as completely as possible for higher on-current level. Junctionless (JL) MOSFETs fully capable of the the conventional NMOSFET operations without p-type channel for enlarging the process margin are under researches. In this paper, the optimum design of the JL MOSFET based on silicon nanowire (SNW) structure is carried out by 3-D device simulation and the basic radio frequency (RF) characteristics such as conductance, maximum oscillation frequency($f_{max}$), current gain cut-off frequency($f_T$) for the optimized device. The channel length was 30 run and the design variables were the channel doping concentration and SNW radius. For the optimally designed JL SNW NMOSFET, $f_T$ and $f_{max}$ high as 367.5 GHz and 602.5 GHz could be obtained, respectively, at the operating bias condition $V_{GS}$ = $V_{DS}$ = 1.0 V).

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2017.04a
• /
• pp.87-87
• /
• 2017

농산물의 품질 및 성분을 측정하는데 있어 기존의 화학적 분석 방식은 정밀도가 높으나 측정에 소요되는 시간과 비용이 많이 들어, 현장 적용하기에는 한계가 있다. 일반적으로 근적외선 분광 분석(Near Infra Red Spectroscopy, NIRS) 방법은 가공 과정에 따라 빠르게 변화되는 단백질 조성 및 수분함량 측정 등에 이용되고 있다. 분석에 소요 시간이 많이 걸리는 켈달법(Kjeldahi method)에 비해 NIR 분광 분석을 통한 보정으로 연속적인 모니터링이 가능하다. 본 연구에서 사용된 시료를 고정시키기 위한 프레임을 제작한 후 NIR센서와 광원인 LED의 각도를 고정시키고 측정 대상체인 사절된 감자 크기에 따라 시료를 고정시킬 수 있는 프레임을 반사면에 위치시켰다. 확산 반사법을 이용하여 프레임에 씨감자 시료를 고정 시킨 후 백색 LED를 이용하여 감자 표면에 빛을 반사시켜 3일 동안 12시간 마다 해당 시료들(열처리, 비누용액 침지, 생감자)의 스펙트럼을 측정하였다. 해당 시료들은 측정 기간 동안 저온상태($4^{\circ}C$)와 실온상태($20^{\circ}C$)에서 보관되었다. 실험 결과는 파장대 145nm에서 저온상태에서 보관된 생감자는 시간경과에 따른 흡광도의 결정 계수값($r^2$)은 0.98 이었다. 이는 감자가 저온에서 생감자의 상태 변화가 일어나고 있다는 것을 의미하고 파장대 145nm에서 시간에 따른 저온상태에서 보관한 감자의 상태 변화 예측이 가능함을 의미한다. 비누용액에 침지시킨 후 실온에 보관한 감자는 시간이 경과함에 따라 파장이 증가함에 따라 흡광도가 증가하였다. 이는 감자에 들어있는 Polyphenol Oxidase 함량 변화로 갈변 현상이 일어난 것을 알 수 있다. 또한 실온에서 보관한 생감자도 시간 경과에 따라 갈변 현상이 일어났지만 용액에 침지시킨 감자보다는 갈변 현상이 36시간 이후로 발견되었다. 열처리 후 실온에서 보관한 감자의 경우에는 갈변현상이 나타나지 않았다. 저온상태에서 보관한 감자시료들 모두 갈변형상이 나타나지 않았지만, 24시간이 지난 후 용액에 침지시킨 감자는 갈변 현상이 발생되었다. 생감자와 열처리한 감자는 시간 경과에 따른 갈변현상이 일어나지 않았으므로, 감자의 갈변현상은 감자의 표면 처리 방법에 국한되지 않고 온도에 영향을 더 많이 받는다는 것을 나타내고 있다. 본 연구는 향후 감자의 품질 및 성분 측정에서 간편하게 사용될 수 있는 감자의 품질 계측 기술에 기여할 것으로 판단된다.

• Korean Journal of Materials Research
• /
• v.22 no.9
• /
• pp.476-481
• /
• 2012

Among the various roll-to-roll printing technologies such as gravure, gravure-offset, and reverse offset printing, reverse offset printing has the advantage of fine patterning, with less than 5 ${\mu}m$ line width. However, it involves complex processes, consisting of 1) the coating process, 2) the off process, 3) the patterning process, and 4) the set process of the ink. Each process demands various ink properties, including viscosity, surface tension, stickiness, and adhesion with substrate or clich$\acute{e}$; these properties are critical factors for the printing quality of fine patterning. In this study, Ag nano ink was developed for reverse offset printing and the effect of polyvinylpyrrolidone(PVP), used as a capping agent of Ag nano particles, on the printing quality was investigated. Ag nano particles with a diameter of ~60 nm were synthesized using the conventional polyol synthesis process. Ethanol and ethylene glycol monopropyl ether(EGPE) were used together as the main solvent in order to control the drying and absorption of the solvents during the printing process. The rheological behavior, especially ink adhesion and stickiness, was controlled with washing processes that have an effect on the offset process and that played a critical role in the fine patterning. The electrical and thermal behaviors were analyzed according to the content of PVP in the Ag ink. Finally, an Ag mesh pattern with a line width of 10 ${\mu}m$ was printed using reverse offset printing; this printing showed an electrical resistivity of 36 ${\mu}{\Omega}{\cdot}cm$ after sintering at $200^{\circ}C$.

• Journal of Sensor Science and Technology
• /
• v.27 no.5
• /
• pp.317-327
• /
• 2018

Terahertz (THz) time-domain spectroscopy(TDS), imaging techniques, and related systems have become mature technologies, widely used in many universities and research laboratories. However, the development of creative technologies still requires improved THz application systems. A few key points are discussed, including the innovative advances of mode-locking energy-emitting semiconductor lasers and better photoconductive semiconductor quantum structures. To realize a compact, low cost, and high performance THz system, it is essential that THz spectroscopy and imaging technologies are better characterized by semiconductor and nano-devices, both static and time-resolved. We introduce the THz spectroscopy and imaging systems, the OSCAT(Optical Sampling by laser CAvity Tuning) system and the ASOPS(ASynchronous Optical Sampling) system, are constructed by our research team. We report on the THz images obtained from their use.

• Journal of the Korean Wood Science and Technology
• /
• v.41 no.4
• /
• pp.302-309
• /
• 2013

The highly porous cellulosic aerogels were prepared by freeze-drying method using sodium hydroxide-urea aqueous solution in the process of dissolution, gelation, regeneration and organic solvent substitution. The structural characteristics of porous aerogel were analyzed using scanning electron microscopy and nitrogen adsorption apparatus. As a result, the dissolving pulp was completely dissolved, but filter papers and holocellulose were divided into two layers (dissolved and undissolved parts) in the process of centrifugation. The structure of aerogel from dissolved pulp showed porous pores in the surface and net-shaped network in the inner part. Aerogels from filter paper and holocellulose had the condensed porous network surface and the open-pore nano-fibril network inner structure. Undissolved form of fibers was observed in the aqueous solution of aerogel from holocellulose. The BET value ($S_{BET}$) of aerogel from dissolved pulp was ranged in 260~326 $m^2/g$, and it was decreased with the increase of concentration. Whereas, the $S_{BET}$ value of aerogel from filter paper (198~418 $m^2/g$) was increased with the increase of concentration. The $S_{BET}$ value of aerogel from holocellulose were 137 $m^2/g$ at 2% (w/w) of cellulose, and it was increased to maximum 401 $m^2/g$ at 4% (w/w) of cellulose. Then, it was decreased at 5% (w/w) of cellulose.

• Proceedings of the Korean Society of Dyers and Finishers Conference
• /
• 2012.03a
• /
• pp.63-63
• /
• 2012

전자제품 패키지에 요구되는 쿠션성과 정전방전 기능을 갖는 폴리우레탄 발포 필름의 제조기술을 확립하게 되면 IT산업용에 적용 가능한 필름제품이 개발되어 ESD(정전방전, Electrostatic Dissipation) 성능을 발휘하게 됨으로서 정전기 쇼크에 의한 각종 전자제품의 오작동이나 파손 방지가 가능하게 되어 포장재, 자동차 전자제품의 하우징 등으로 사용될 수 있게 된다. 전도성 고분자인 Polyaniline (PANI)은 다른 여러 고분자와 비교하여 볼 때 다른 유형의 전도성 고분자보다 합성하기가 쉽고 높은 전기전도도를 보임은 물론 열적 및 대기 안정성이 우수하며 가격이 저렴한 장점을 가지고 있다. 본연구는 CNT 나노기술을 응용한 IT산업용 적층간지용 ESD PU발포필름의 제조 가공기술 및 상품화 개발을 수행하고자 방수, 투습방수성을 가지는 유연재료인 폴리우레탄(PU)의 1액형 PU와 DMF에 PANI의 함량을 5, 10, 15, 20, 25, 30wt%로 변화시켜 제조한 PANI/DMF 분산용액과 IPA/MWNT 3wt% 분산용액의 혼용비에 변화를 주어 $120^{\circ}C$에서 2분 건조시켜 그라운드 필름을 제조하였다. 그리고 2액형 PU와 IPA/MWNT 3wt% 분산용액과 발포제를 사용하여 발포온도 $150^{\circ}C$에서 5분간 건조시켜 발포필름을 제조하였으며 이들의 전기적 특성과 역학적 특성을 조사하였다. 제조된 필름의 전기전도성은 전기저항측정기 KEITHLEY 8009를 사용하여 부피저항과, 표면저항을 각각 측정하여 확인하였으며, 필름의 마찰 대전압은 E.S.T-7 마찰 대전압 시험기를 이용하여 표면 마찰 대전압을 측정하여 확인하고, 필름의 물리적 특성은 인장시험기를 이용하여 breaking stress, breaking strain을 측정하였다. 필름단면의 CNT 발포특성은 주사전자현미경(SEM)을 사용하여 측정하여 발포특성과 물성과의 연관성을 확인하였다. 그 결과 필름의 전기적 특성은 PANI가 30% 함량일 때 전반적으로 낮은 저항값이 측정되었으며, 마찰대전압을 측정한 결과 대부분의 시료가 0에 가까운 낮은 값을 가졌다. 필름의 물리적 인장특성은 PANI가 10wt%의 함량일 때 가장 높은 절단강도를 가졌으며 분산용액의 혼용비에 따른 경향성은 나타나지 않았다. 필름의 단면형상을 확인하여 발포특성을 분석한 결과 PANI의 함량에 따라 발포 cell의 크기는 뚜렷한 경향성을 보이지 않았으나 30wt%의 PANI/DMF 분산용액 20part(gr)와 3wt% IPA/MWNT 분산용액 40part(gr)로 제조한 시료의 cell이 가장 균일하고 고르게 발포되었으며, 3.90E+06ohm으로 가장 낮은 표면저항 값으로 측정되어 가장 좋은 전기전도성을 가짐을 확인하였다.

• Journal of Biosystems Engineering
• /
• v.36 no.5
• /
• pp.342-347
• /
• 2011

The effect of SNC(silver nano colloid) on the emission reduction of odors such as ammonia ($NH_3$), hydrogen sulfide ($H_2S$), and methane ($CH_4$) from swine excreta was studied. Silver has been used as an universal antibiotic substance and can reduce the emission of some gases by sterilizing action. Therefore, an apparatus which produces SNC was developed and was conducted its performance test. Also, the SNC made by the apparatus was applied to swine excreta sampled from a piggery in oder to find the effect on the reduction of odor emission. An electrolysis apparatus was developed to produce SNC and its capacity was 0.024 ppm/$hr{\cdot}L$. The effects of SNC on the reduction of odor emission from swine excreta were tested for bad smell gases of ammonia ($NH_3$), hydrogen sulfide ($H_2S$) and methane ($CH_4$). For ammonia gas, factorial experiments were conducted to find the effects of concentration and application rate of SNC. The test results for the different concentrations of 20 ppm, 50 ppm, and 100 ppm showed that the more concentration of SNC was increased, the more emission reduction of ammonia gas increased. From the test results about the effect of application rate, the more SNC was applied, the more emission reduction of $NH_3$ increased. In order to reduce the concentration of $NH_3$ below 5 ppm, SNC of 50 ppm is recommended to be applied at an interval of 6 hours, and is mixed with swine excreta in the volumetric ratio of 4:1. For hydrogen sulfide gas, the concentration was decreased as time went by and was reduced rapidly in the first stage of the tests for all applied concentrations of SNC (20 ppm, 50 ppm, and 100 ppm). Especially, when 100 ml of SNC with 100 ppm was applied, emission of hydrogen sulfide gas was reduced rapidly during early 4 hours after the application of SNC. And, concentration of hydrogen sulfide gas was maintained below 20 ppm after 12 hours. For methane gas, t-test showed that there was no significance on the effect of its application for all applied concentrations of SNC. Therefore, it was concluded that the application of SNC on swine excreta had no effect on the emission reduction of $CH_4$.