• International Journal of Costume and Fashion
• /
• v.4 no.2
• /
• pp.45-55
• /
• 2004

Rapid informatization and technology advance in the 21st century has invited a new paradigm and changed many things in human life pattern. The impact of mobility seen in this digital nomadism has brought about, when it comes to clothing, a change in its unique meaning, that is, the graftage of high technology onto present nomad's life style who live moving around all the time due to the expansion of mobile environment. As the fruits of this expansion of mobile environment and technology advance in wireless telecommunication, easy-to-carry smaller sized devices such as cell phones, PDA, and MP3 players represent the present times, while the future would be an 'era of wearing' in which kinds of electronic devices and systems are integrated into clothing. Thus in this study, concept of wearable computer seen in the 21st century's digital nomadism was reviewed, and figurativeness and anesthetic value of wearable computer were discussed in association with the change in high style image resulted from technology advance and change of life style. By drawing a justice from which, value of future fashion was also prospected.

• Journal of the Microelectronics and Packaging Society
• /
• v.15 no.4
• /
• pp.25-29
• /
• 2008

Reliability and performance in metal gate/high-k device with multiple gate dielectrics were investigated. MOSFETs with a thin $HfSiO_x$ layer on a thermal Si02 dielectric as gate dielectrics exhibit excellent mobility and low interface trap density. However, the distribution of threshold voltages of $HfSiO_x/SiO_2$ stack devices were wider than those of $SiO_2$ and $HfSiO_x$ single layer devices due to the penetration of Hf and/or intermixing of $HfSiO_x$ with underlying $SiO_2$. The results of TZDB and SILC characteristics suggested that a certain portion of $HfSiO_x$ layer reacted with the underlying thick $SiO_2$ layer, which in turn affected the reliability characteristics.

• Journal of electromagnetic engineering and science
• /
• v.17 no.4
• /
• pp.178-180
• /
• 2017

This study presents a 2-20 GHz monolithic distributed power amplifier (DPA) using a $0.25{\mu}m$ AlGaN/GaN on SiC high electron mobility transistor (HEMT) technology. The gate width of the HEMT was selected after considering the input capacitance of the unit cell that guarantees decade bandwidth. To achieve high output power using small transistors, a 12-stage DPA was designed with a non-uniform drain line impedance to provide optimal output power matching. The maximum operating frequency of the proposed DPA is above 20 GHz, which is higher than those of other DPAs manufactured with the same gate-length process. The measured output power and power-added efficiency of the DPA monolithic microwave integrated circuit (MMIC) are 35.3-38.6 dBm and 11.4%-31%, respectively, for 2-20 GHz.

• Korean Journal of Materials Research
• /
• v.26 no.11
• /
• pp.635-643
• /
• 2016

Graphene has shown exceptional properties for high performance devices due to its high carrier mobility. Of particular interest is the potential use of graphene nanoribbons as field-effect transistors. Herein, we introduce a facile approach to the fabrication of graphene nanoribbon (GNR) arrays with ~200 nm width using nanoimprint lithography (NIL), which is a simple and robust method for patterning with high fidelity over a large area. To realize a 2D material-based device, we integrated the graphene nanoribbon arrays in field effect transistors (GNR-FETs) using conventional lithography and metallization on highly-doped $Si/SiO_2$ substrate. Consequently, we observed an enhancement of the performance of the GNR-transistors compared to that of the micro-ribbon graphene transistors. Besides this, using a transfer printing process on a flexible polymeric substrate, we demonstrated graphene-silicon junction structures that use CVD grown graphene as flexible electrodes for Si based transistors.

• Journal of KIISE
• /
• v.44 no.7
• /
• pp.726-732
• /
• 2017

In practical distributed sensing and prediction applications over wireless sensor networks (WSN), environmental sensing activities are highly dynamic because of noisy sensory information from moving source signals. The recent distributed online convex optimization frameworks have been developed as promising approaches for solving approximately stochastic learning problems over network of sensors in a distributed manner. Negligence of mobility consequence in the original distributed saddle point algorithm (DSPA) could strongly affect the convergence rate and stability of learning results. In this paper, we propose an integrated sliding windows mechanism in order to stabilize predictions and achieve better convergence rates in cooperative detection of a moving source signal scenario.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.10
• /
• pp.2909-2912
• /
• 2010

Hydrogenated microcrystalline silicon (${\mu}c$-Si:H) thin film for solar cells is prepared by plasma-enhanced chemical vapor deposition and physical properties of the ${\mu}c$-Si:H p-layer has been investigated. With respect to stable efficiency, this film is expected to surpass the performance of conventional amorphous silicon based solar cells and very soon be a close competitor to other thin film photovoltaic materials. Silicon in various structural forms has a direct effect on the efficiency of solar cell devices with different electron mobility and photon conversion. A Raman microscope is adopted to study the degree of crystallinity of Si film by analyzing the integrated intensity peaks at 480, 510 and $520\;cm^{-1}$, which corresponds to the amorphous phase (a-Si:H), microcrystalline (${\mu}c$-Si:H) and large crystals (c-Si), respectively. The crystal volume fraction is calculated from the ratio of the crystalline and the amorphous phase. The results are compared with high-resolution transmission electron microscopy (HR-TEM) for the determination of crystallinity factor. Optical properties such as refractive index, extinction coefficient, and band gap are studied with reflectance spectra.

• Journal of Korean Academy of Rural Health Nursing
• /
• v.12 no.1
• /
• pp.13-27
• /
• 2017

Purpose: The purpose of this study is to identify health-related factors, especially for the elderly who are subject to visiting health care at vulnerable populations. Methods: Tools were Guide to Community Integrated Health Promotion Project 2016, Visit Health Care Health Interview Survey, measures of physical function, motor skills, composite mobility, BMI, and subjective fitness levels. Depression was measured with the Short Results: Older elders living alone were more vulnerable than those with living others. Elders with less education showed greater weakness but the difference was not significant. Average scores for frailty were 2.21 (healthy group), 7.66 (high-risk group) and 15.69 (frail group). Scores based on weakness level differed significantly with the exception of nutrition. Nine out of 10 elders in disadvantaged areas were in the frail group or at high risk. Conclusion: Results support the goal to maintain/improve physical/mental functions through individual management of high-risk/frail older adults at risk of becoming infirm. It is imperative to implement a public health care delivery system to ensure programs are operated effectively and personalized.

• Proceedings of the IEEK Conference
• /
• 2002.06a
• /
• pp.167-170
• /
• 2002

The design and fabrication of Q-band 3-stage monolithic microwave integrated circuit(MMIC) driver and power amplifiers for WLAN are presented using 0.2${\mu}{\textrm}{m}$ AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistor(PHEMT). In each stage of the MMIC DA, a negative feedback is used for both broadband and good stability. The MMIC PA has employed a balanced configuration to overcome these difficulties and achieve high power with low VSWR over a wide frequency range. In the MMIC DA, the measurement results arc achieved as an input return loss under -4dB, an output return loss under -l0dB, a gain of 14dB, and a PldB of 17dB at C-band(36~ 44GHz). The chip size is 28mm$\times$1.3mm. The developed MMIC PA has the l0dB linear gain over 360Hz to 420Hz band and 22dBm PldB performance at 400Hz. The size of fabricated MMIC PA is 4mm x3mm. These results closely match with design results. This MMIC DA Sl PA will be used as the unit cells to develop millimeter-wave transmitters for use in wideband wireless LAN systems.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.6B
• /
• pp.573-587
• /
• 2003

Due to the growth of mobile communication and the popularization of Internet, it is expected that wired and wireless communication network of the next generation will be integrated and flourished with IP-based. There have been a great deal of research efforts to provide mobile IP service onthe existing lower layer. The location update and the paging scheme is one of the most challenging technical issues for this topic. In this thesis, a paging method based on the distance-based location update scheme is proposed for IP network to support mobility in layer 3. The proposed scheme is implemented and verified with the OPNET.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.14 no.6
• /
• pp.1097-1106
• /
• 2011

Tactical Information Communication Network(TICN), a concept-type integrated Military Communication system that enables precise command control and decision making, is designed to advance into high speed, large capacity, long distance wireless relay transmission. To support mobility in battlefield environments, the application of Ad-hoc networking technology to its wireless communication has been examined. Ad-hoc network works properly only if the participating nodes cooperate in routing and packet forwarding. However, if selfish nodes not forwarding packets of other nodes and malicious nodes making the false accusation are in the network, it is faced to many threats. Therefore, detection and management of these misbehaving nodes is necessary to make confident in Ad-hoc networks. To solve this problem, we propose an efficient intrusion detection technique to detect and manage those two types of attacks. The simulation-based performance analysis shows that our approach is highly effective and can reliably detect a multitude of misbehaving node.