• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.7
• /
• pp.1740-1749
• /
• 2009

As mobile devices evolve and digital convergence trend is here to stay, mobile phones are built with multiple functions including cameras, MP3s, TVs and game consoles. As a consequence, such multi-functional mobile phones come to spend more power, facilitating development of next-generation ultra-capacity lithium ion battery. In addition, environmental regulations and rising oil prices cause demand for hybrid cars to keep rising. Accordingly, more and more attention is being paid to medium and large batteries and more efforts are being made to realize lower battery prices, higher outputs and stability. This study presented a patent technology related to the lithium ion battery packing that allows reducing processes related, increasing productivity and recycling parts other than the body. The lithium ion battery pack to which protection circuits are elastically attached provides short circuit protection for the circuit and the body and makes electric connection of the circuit and the body easier.

• Journal of Korean Neurosurgical Society
• /
• v.38 no.6
• /
• pp.435-441
• /
• 2005

Objective : Expandable cage used for spinal reconstruction after corpectomy has several advantages over nonexpendable cages. Here we present our clinical experience with the use of this cage after anterior column corpectomy with an average of one year follow up. Methods : Ten patients underwent expandable cage reconstruction of the anterior column after single-level or multilevel corpectomy for various cervical spinal disorders. Anterior plating with or without additional posterior instrumentation were performed in all patients. Functional outcomes, complications, and radiographic outcomes were determined. Results : There was no cage-related complication. Functionally, neurological examination revealed improvement in 7 of 10 patients and no patient had neurological deterioration after the surgery. Immediate stability was achieved and maintained throughout the period of follow-up. There was minimal subsidence [<2mm] noticeable in three of the cases that underwent a two-level corpectomy. Subsidence was noted in osteoporotic patients and patients undergoing multi-level corpectomies. Average pre-operative kyphotic angle was 9 degrees. This was corrected to an average of 5.4 degrees in lordosis postoperatively. Conclusion : In conclusion, expandable cages are safe and effective devices for vertebral body replacement after cervical corpectomy when used in combination with anterior plating with or without additional posterior stabilization. The advantages of using expandable cages include its ability to easily accommodate itself into the corpectomy defect, its ability to tightly purchase into the end plates after expansion and thus minimizing the potential for migration, and finally, its ability to correct kyphosis deformity via its in vivo expansion properties.

• Journal of Aerospace System Engineering
• /
• v.18 no.4
• /
• pp.53-60
• /
• 2024

We developed a coin cell battery using high-strength carbon fiber and glass fiber, taking a preliminary step toward creating a battery that supports structural loads and stores energy, with potential applications in satellite structures. High-strength fiber-based electrodes and electrolytes were fabricated and applied to coin cells to evaluate their electrochemical performance. Consequently, the discharge capacities under continuous charge/discharge cycles and high discharge rates of 2 C-rate were determined to be 122.9 and 103.5 mAh/g, respectively, indicating that high-strength fibers can replace conventional battery components. Although current performance is lower than that of commercial batteries, this research has demonstrated significant potential as foundational work for multi-functional energy storage devices and is expected to contribute to the development of structural batteries for satellite applications.

• Fiber Technology and Industry
• /
• v.2 no.4
• /
• pp.490-508
• /
• 1998

One of the latest fields of research in the area of output devices is tactual display devices [13,31]. These tactual or haptic devices allow the user to receive haptic feedback output from a variety of sources. This allows the user to actually feel virtual objects and manipulate them by touch. This is an emerging technology and will be instrumental in enhancing the realism of wearable augmented environments for certain applications. Tactual displays have previously been used for scientific visualization in virtual environments by chemists and engineers to improve perception and understanding of force fields and of world models populated with the impenetrable. In addition to tactual displays, the use of wearable audio displays that allow sound to be spatialized are being developed. With wearable computers, designers will soon be able to pair spatialized sound to virtual representations of objects when appropriate to make the wearable computer experience even more realistic to the user. Furthermore, as the number and complexity of wearable computing applications continues to grow, there will be increasing needs for systems that are faster, lighter, and have higher resolution displays. Better networking technology will also need to be developed to allow all users of wearable computers to have high bandwidth connections for real time information gathering and collaboration. In addition to the technology advances that make users need to wear computers in everyday life, there is also the desire to have users want to wear their computers. In order to do this, wearable computing needs to be unobtrusive and socially acceptable. By making wearables smaller and lighter, or actually embedding them in clothing, users can conceal them easily and wear them comfortably. The military is currently working on the development of the Personal Information Carrier (PIC) or digital dog tag. The PIC is a small electronic storage device containing medical information about the wearer. While old military dog tags contained only 5 lines of information, the digital tags may contain volumes of multi-media information including medical history, X-rays, and cardiograms. Using hand held devices in the field, medics would be able to call this information up in real time for better treatment. A fully functional transmittable device is still years off, but this technology once developed in the military, could be adapted tp civilian users and provide ant information, medical or otherwise, in a portable, not obstructive, and fashionable way. Another future device that could increase safety and well being of its users is the nose on-a-chip developed by the Oak Ridge National Lab in Tennessee. This tiny digital silicon chip about the size of a dime, is capable of 'smelling' natural gas leaks in stoves, heaters, and other appliances. It can also detect dangerous levels of carbon monoxide. This device can also be configured to notify the fire department when a leak is detected. This nose chip should be commercially available within 2 years, and is inexpensive, requires low power, and is very sensitive. Along with gas detection capabilities, this device may someday also be configured to detect smoke and other harmful gases. By embedding this chip into workers uniforms, name tags, etc., this could be a lifesaving computational accessory. In addition to the future safety technology soon to be available as accessories are devices that are for entertainment and security. The LCI computer group is developing a Smartpen, that electronically verifies a user's signature. With the increase in credit card use and the rise in forgeries, is the need for commercial industries to constantly verify signatures. This Smartpen writes like a normal pen but uses sensors to detect the motion of the pen as the user signs their name to authenticate the signature. This computational accessory should be available in 1999, and would bring increased peace of mind to consumers and vendors alike. In the entertainment domain, Panasonic is creating the first portable hand-held DVD player. This device weight less than 3 pounds and has a screen about 6' across. The color LCD has the same 16:9 aspect ratio of a cinema screen and supports a high resolution of 280,000 pixels and stereo sound. The player can play standard DVD movies and has a hour battery life for mobile use. To summarize, in this paper we presented concepts related to the design and use of wearable computers with extensions to smart spaces. For some time, researchers in telerobotics have used computer graphics to enhance remote scenes. Recent advances in augmented reality displays make it possible to enhance the user's local environment with 'information'. As shown in this paper, there are many application areas for this technology such as medicine, manufacturing, training, and recreation. Wearable computers allow a much closer association of information with the user. By embedding sensors in the wearable to allow it to see what the user sees, hear what the user hears, sense the user's physical state, and analyze what the user is typing, an intelligent agent may be able to analyze what the user is doing and try to predict the resources he will need next or in the near future. Using this information, the agent may download files, reserve communications bandwidth, post reminders, or automatically send updates to colleagues to help facilitate the user's daily interactions. This intelligent wearable computer would be able to act as a personal assistant, who is always around, knows the user's personal preferences and tastes, and tries to streamline interactions with the rest of the world.

• Korean Journal of Materials Research
• /
• v.1 no.1
• /
• pp.46-53
• /
• 1991

The stress of PSG (Phosphosilicate glass), USG (Undoped-silicate grass) and SiN films, which are mainly used as passivation layers in semiconductor memory devices, deposited by CVD methods has been studied as a function of film thickness and holding time in air. The stress of the PSG film or the USG film is increased in tensile state with increasing film thickness. On the other hand the stress level of the SiN film in compressive stress does not change as film thickness changes. The stress of PSG film shows the drastic change from the tensile stress to the compressive stress after the film is left 2 days in air. FTIR spectra indicated that the stress variation was due to the penetration of water molecule. It looks possible to recover the stress of about $2.5{\times}{10^9}dyne/cm^2$ by annealing treatment at $300^{\circ}C$ for 20min. The total stress of multi-layered films having the PSG film is determined mainly by the stress variation of PSG layer with holding time. The total stress of multi-layered film appears to have a functional relationship with the stress in the thickness of each film. The resistance against stress-migration of sputtered Al line increases with increasing the tensile stress for the PSG film or the USG film.

• Progress in Medical Physics
• /
• v.8 no.1
• /
• pp.53-67
• /
• 1997

General hospitals have being under the influence of various and specific environment of electromagnetic field. The factors are development of medical electric equipment and device with enlarged functional demands, in high power and multi-frequency. It has all of both faces, EMI(electromagnetic interference) and EMS(electromagnetic susceptibility). In additional, expansion of personal communication system(cellular phone) has many unreliable factor of using time and area, making noise of electromagnetic fields. We studied actual conditions of EMI in the medical site, where is numerous medical equipment, especially central operation room and ICU(intensive care unit), AKR(artificial kidney room : hemo-dialysis unit), etc. The influence, most of medical equipments made electromagnetic nosie has various factors in its band of frequency, harmonics and strength. In the experimental use of electro-surgical unit and cellular phone, noticeable and considerable noise of eletromagnetic fields were measured. All of that can make trouble and errors on the steadiness of bioelectrical devices. In conclusion, It is necessary to reconsiderations of reallocating EMI source vs. EMS factor, and set to definite forbiding area of using cellular phone. For maintenance of steady normal conditions, in spite of existing any other legal standards of safty level, it need considering all of alternative electromagnetic situations on a case-by-case basis.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.2
• /
• pp.82-92
• /
• 2008

Recently, many digital signal processing(DSP) applications such as H.264, CDMA and MP3 are predominant tasks for modern high-performance portable devices. These applications are generally computation-intensive, and therefore, require quite complicated accelerator units to improve performance. Designing such specialized, yet fixed DSP accelerators takes lots of effort. Therefore, DSPs with multiple accelerators often have a very poor time-to-market and an unacceptable area overhead. To avoid such long time-to-market and high-area overhead, dynamically reconfigurable DSP architectures have attracted a lot of attention lately. Dynamically reconfigurable DSPs typically employ a multi-functional DSP accelerator which executes similar, yet different multiple kinds of computations for DSP applications. With this type of dynamically reconfigurable DSP accelerators, the time to market reduces significantly. However, integrating multiple functionalities into a single IP often results in excessive control and area overhead. Therefore, delay and power consumption often turn out to be quite excessive. In this thesis, to reduce power consumption of dynamically reconfigurable IPs, we propose a novel fine-grained clock gating scheme, and to reduce size of dynamically reconfigurable IPs, we propose a compact multiplier-less multiplication unit where shifters and adders carry out constant multiplications.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.588-588
• /
• 2013

Nanoscale noble-metals have attracted enormous attention from researchers in various fields of study because of their unusual optical properties as well as novel chemical properties. They have possible uses in diverse applications such as devices, transistors, optoelectronics, information storages, and energy converters. It is well-known that nanoparticles of noble-metals such as silver and gold show strong absorption bands in the visible region due to their surface-plasmon oscillation modes of conductive electrons. Silver nanocubes stand out from various types of Silver nanostructures (e.g., spheres, rods, bars, belts, and wires) due to their superior performance in a range of applications involvinglocalized surface plasmon resonance, surface-enhanced Raman scattering, and biosensing. In addition, extensive efforts have been devoted to the investigation of Gold-based nanocomposites to achieve high catalytic performances and utilization efficiencies. Furthermore, as the catalytic reactivity of Silver nanostructures depends highly on their morphology, hollow Gold nanoparticles having void interiors may offer additional catalytic advantages due to their increased surface areas. Especially, hollow nanospheres possess structurally tunable features such as shell thickness, interior cavity size, and chemical composition, leading to relatively high surface areas, low densities, and reduced costs compared with their solid counterparts. Thus, hollow-structured noblemetal nanoparticles can be applied to nanometer-sized chemical reactors, efficient catalysts, energy-storage media, and small containers to encapsulate multi-functional active materials. Silver nanocubes dispersed in water have been transformed into Ag@Au nanoboxes, which show highly enhanced catalytic properties, by adding $HAuCl_4$. By using this concept, $SiO_2$-coated Ag@Au nanoboxes have been synthesized via galvanic replacement of $SiO_2$-coated Ag nanocubes. They have lower catalytic ability but more stability than Ag@Au nanoboxes do. Thus, they could be recycled. $SiO_2$-coated Ag@Au nanoboxes have been found to catalyze the degradation of 4-nitrophenol efficiently in the presence of $NaBH_4$. By changing the amount of the added noble metal salt to control the molar ratio Au to Ag, we could tune the catalytic properties of the nanostructures in the reduction of the dyes. The catalytic ability of $SiO_2$-coated Ag@Au nanoboxes has been found to be much more efficient than $SiO_2$-coated Ag nanocubes. Catalytic performances were affected noteworthily by the metals, sizes, and shapes of noble-metal nanostructures.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.5B
• /
• pp.385-394
• /
• 2012

The tactical mobile communication network, which comprises a part of the next-generation Tactical Information and Communication Network (TICN), provides means of communication and control for Tactical Multi-Functional Terminals (TMFT) belonging to a Mobile Subscriber Access Point (MSAP). The next-generation of MSAP is capable of constructing a backbone network via LCTR and HCTR directional antennas. At the same time, WMN modules are used to create and manage a wireless mesh backbone. When directional antennas are used in mobile environments, seamless services cannot be efficiently supported as the movement of the node prevents the angle of the antenna to constantly match. Therefore, data communication through the wireless mesh networks is required to provide direct communication between mobile MSAPs. Accordingly, mutual authentication and data encryption mechanisms are required to provide reliable data transmission in this environment. To provide efficient mutual authentication between MSAP devices, the process of verifying a certificate of the other MSAP device through its own authentication server is required. This paper proposes mutual authentication mechanisms where the MSAP requiring authentication and the MSAP that permits it initiates low-cost and efficient authentication in a distributed way. More specifically, we propose a method of applying EAP-ELS (Extensible Authentication Protocol-Transport Layer Security) in the next-generation TICN.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.28 no.11
• /
• pp.902-915
• /
• 2017

In recent years, mobile devices have become increasingly multi-functional and high performance, resulting in a dramatical increase in processing speed. On the other hand, the size of device is reduced, circuits inside the device are more easily exposed to electromagnetic interference radiated from antenna or adjacent circuits, degrading the system performance. To prevent this, it is necessary to design the device considering the electromagnetic characteristics with EM simulation at the design stage of product. However, the EM simulation takes a long analysis time and require high-level system resources for fast analysis. In this paper, an equivalent circuit modeling method for a round wire is proposed using a PEEC method and the electromagnetic coupling from a dipole antenna to a transmission line is analyzed in frequency domain. And compared with the result of electromagnetic simulator. As a result, PEEC method shows good agreement with those of electromagnetic simulation, in a much more short time.