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WLAN (IEEE 802.11a)/VMAN (IEEE 802.16a) dual mode transceiver chip has been proposed, designed and fabricated. Transceiver RF IC chip with packaged size of 6 mm*6 mm was fabricated using 0.25 um SiGe BiCMOS process. Power amplifier and PLL/VCO chip were fabricated using the same process. Ceramic front-end filter were also fabricated for WLAN/WMAN frequencies. To make compact transceiver system, these chips was mounted on 2 cm*2 cm double side PCB. The full system has been tested with external ADC/DAC and baseband modem. The measured results show that fabricated transceiver system meets the requirements for WLAN/WMAN standards

The silicon-through-via structure that can withstand high thermal budget of MEMS process is suggested for stacked MEMS package. The doped silicon is used as through- via material instead of metal. The key ideas and design are described in detail. SDB (silicon direct bonding) multi-stacking process and metal reflow technique are used for through-via fabrication. Through-via arrays with 40mum and 50mum spacing are fabricated. Resistance of the fabricated via is measured. The thermal characteristics of the silicon through-via are under evaluation

We established a novel method to fabricate a micro-machine that can actuate for long-term in physiological condition. Backbone of micro machine is built with bio-compatible material of PDMS by using specially designed 3D molding aligner. The high generative force of hybrid actuator is realized based on selective cell culture on groove surface that leads higher concentration of cells. Those key techniques enable the developed micro-machines to work for two weeks in medium condition. For performance demonstration of micro-machine, we construct a tripod micro-machine and observe sustained and synchronous locomotion in medium condition for almost two weeks-period.

For the application to optic devices, wafer level package including spacer with particular thickness according to optical design could be required. In these cases, the uniformity of spacer thickness is important for bonding strength and optical performance. Packaging process has to be performed at low temperature in order to prevent damage to devices fabricated before packaging. And if photosensitive material is used as spacer layer, thickness of spacer and size and shape of pattern can be easy to control. This paper presents polymer bonding with thick, uniform and patterned spacing layer using SU-8 2100 photoresist for wafer level package. SU-8, negative photoresist, can be coated uniformly by spin coater and is cured at 95degC and bonded well near the temperature. It can be bonded to silicon well, patterned with high aspect ratio and easy to form thick layer due to its high viscosity. It is also mechanically strong, chemically resistive and thermally stable. But adhesion of SU-8 to glass is poor, and in the case of forming thick layer, SU-8 layer leans from the perpendicular due to imbalance to gravity. To solve leaning problem, the wafer rotating system was introduced. Imbalance to gravity of thick layer was cancelled out through rotating wafer during curing time. And depositing additional layer of gold onto glass could improve adhesion strength of SU-8 to glass. Conclusively, we established the coating condition for forming patterned SU-8 layer with 400 mum of thickness and 3.25% of uniformity through single coating. Also we performed silicon to glass bonding with thick, uniform and patterned spacing layer of SU-8 photoresist for wafer level package

This paper reports RF MEMS switch that has low actuation voltage and high isolation characteristics. We propose see-saw type RF MEMS switch based on a single crystalline silicon structure with fine gap vertical comb. Low voltage actuation and high isolation characteristics are key features to be solved in electrostatic RF switch design. Since these parameters in the conventional parallel plate MEMS switch design are in trade-off relation, both requirements cannot be met simultaneously. In vertical comb design, however, the actuation voltage is independent to the vertical separation distance between the contact electrodes. Then, we can design the large separation distance between contact electrodes to get high isolation. We have designed and fabricated a RF MEMS switch which has -46 dB isolation loss at 5 GHz, -0.9 dB insertion loss at 5 GHz and 40 V operation voltage.

A novel Si via interconnection technique using the doped silicon as an interconnection material is presented for 3D MEMS package. Concept and key idea of silicon via is described. Two layers stacked via arrays with 40 mum and 50 mum spacing are fabricated to prove its feasibility. SDB (silicon direct bonding) multi-stacking process is used for fabrication of stacked package, which consists of a substrate, MEMS structure layer and a cover layer. Resistance of the via which has 34 mum width is measured. Additional electrical and mechanical characteristics of fabricated via are under testing.

Carbon nanotubes (CNTs) is one of the most attractive materials for field emission tip. Because of its low threshold voltage and high current density. In this article we introduce a new simple process to fabricate self-aligned carbon nanotubes for field emission tip with simple process. We can make the less than 200nm diameter hole with our one mask like process by which carbon nanotubes will be self-aligned with the gate layer. And then carbon nanotubes will be catalytically grown in PECVD chamber.

Web-based instruction has a lot of potential power in constructivism learning theory, and multimedia-based learning is able to provide natural learning environments. However, existing e-learning platforms have a limitation to provide multimedia learning objects on the web because of network traffic problems, which make it difficult to use a large amount of multimedia learning objects or a synchronous video streaming in e-learning. In this paper, we propose an adaptive QoS architecture to use the large amount of multimedia and realtime multimedia pedagogically for e-learning. First, we introduce the pedagogical issues and adaptive issues. And then we describe the adaptive strategies and architecture to support adaptive QoS. The purpose of this paper is to contribute towards understanding how to support adaptive QoS for service-oriented learning environments of e-learning.

A novel electron beam lithography system, microcolumn, was designed and fabricated using a wafer stacking and double metal interconnection process. This is the first monolithic microcolumn. All electrodes were made of highly doped Si wafer and Pyrex glass was used as an insulator. The system was assembled using a glass jig and several alignment methods including a conventional method using an aligner, laser diffraction image and refracted light were used and the misalignment was less than 10/spl mu/m. Anodic bonding was performed and the process condition was optimized to reduce the stress. The size of 3/spl times/3 arrayed microcolumn system including jig is 50mm /spl times/ 50mm and the height is 6.5mm. The size of 1 column is 6mm /spl times/ 6mm and it is the smallest size.

We successfully demonstrate that a thermally actuated reversible hydrogel based clamper, the poly N-isopropylacrylamide (PNIPAAm), holds the intestines of a pig during the inchworm motion of microrobot. Although there are no direct relationship between hydro affinity and friction force, we found a significant friction force difference according to the surface condition change of PNIPAAm hydrogel. On the small intestine of a pig, a clamping mechanism was realized based on simple switching hydrophobic/hydrophilic surface conditions of PNIPAAm due to heating/cooling. In order to estimate the response time of the clamper, the characteristic transition time of PNIPAAm film from hydrophilic to hydrophobic condition was investigated. Water contact angle (WCA) was monitored to normalize the transition time characteristics over the course of time. From these results, we calculated the minimum heating time of the various thickness of film to the clamping after its change to the hydrophobic condition. The minimum heating time was 15 seconds until 1 mm thickness of PNIPAAm film had enough friction force.

Inertial-grade vertical-type and lateral-type differential resonant accelerometers (DRXL) are designed, fabricated and tested for navigation application, using one mask process. The accelerometers consist of an out-of-plane (for z-axis) accelerometer and in-plane (for x, y-axes) accelerometers. The sensing principle of the accelerometer is based on gap-sensitive electrostatic stiffness changing effect. It says that the natural frequency of the accelerometer can be changed according to an electrostatic force on the proof mass of the accelerometer. The out-of-plane resonant accelerometer shows bias stability of 2.5 /spl mu/g, sensitivity of 70 Hz/g and bandwidth of 100 Hz at resonant frequency of 12 kHz. The in-plane resonant accelerometer shows bias stability of 5.2 /spl mu/g, sensitivity of 128 Hz/g and bandwidth of 110 Hz at resonant frequency of 23.4 kHz. The measured performance of two accelerometers are suitable for an application of inertial navigation.

In this paper, we describe that it is possible to conduct the pretreatment reaction procedure for the disease diagnosis by using just single chip with nanoliter sample consumption. A PDMS micro-pillar with a diameter and height of 30 /spl mu/m was developed for bead platform. The micro reaction chamber that is surrounded by the PDMS pillar structure has 90 nanoliter volume. (3 mm /spl times/ 1 mm /spl times/ 30 /spl mu/m) After filling the reaction chamber with micro beads, biotin, streptavidin and antibody are flowed to react with each other on the bead surface using microfluidic flow. It takes about just 20 minutes to make antibody immobilization. Alpha feto protein (AFP) was tested for the application of our micro chips. Fluorescein conjugated AFP was analyzed with confocal microscope. We successfully demonstrated the AFP detection capability from 10/sup -9/ to 10/sup -6/ g/ml which is over the desired range of AFP concentration in clinic. These bead reactions are 3D reaction unlike the 2D reaction of standard surface immobilization process. Therefore, the consumption of the sample and antibody solution is minimized and the sensitivity is enhanced. In addition, we have investigated the effects of parameters such as flow rate, pH and temperature, which are the crucial reaction parameters. We could also demonstrate that it is possible to concentrate AFP over 50 folded times by continuous AFP flowing while injecting it into microchip.

We propose a novel fabrication method for implementing a high precision capacitive type microaccelerometer with uniform nanometer scale gap and have fabricated a nano-gap accelerometer with 135 nm gap and high aspect ratio (>60:1) using modified photo-assisted electrochemical etching. The characteristics of the etching were observed according to the DC bias, the light intensity, and the pitch. After obtaining the optimum etching conditions, the accelerometer with 135 nm sensing gap was designed and fabricated using a 4 masks process.

We developed a vertically guided MEMS probe card with deeply recessed trench-type cantilever. This probe card was designed to achieve a displacement of 50 /spl mu/m at a force of 1.5 gram. The measured contact resistance was about 0.4 ohm for 50 /spl mu/m displacement. The leakage current between the shortest tips was approximately 10 pA. To implement fine pitch and make a vertically guided structure, a cantilever beam was formed inside the trench after deep RIE silicon etching. This probe card was capable of a 35 /spl mu/m pad pitch.

In this paper, MEMS comb structures with several tens of nanometer gap and ultra high aspect ratio more than 125:1 has been achieved using modified photo-assisted electro-chemical etching method. It is possible to control the gap of the comb structure from 50 nm to 1 /spl mu/m by adjusting the intensity of the light source, which is unusually blue LED (light emitting diodes) in this experiment. By changing the bias and the composition of electrolyte that consists of H/sub 2/O or DMF (dimethyl-formamide) based 5% HF (hydrofluoric acid) and 20% ethanol as a wetting agent, the characteristics of the etching were observed. Finally MEMS comb structure with uniform 200 nm gap and 25 /spl mu/m depth was well defined.

Frequency-based mining of association rules sometimes suffers rule quality problems. In this paper, we introduce a new measure called surprisal that estimates the informativeness of transactional instances and attributes. We eliminate noisy and uninformative data using the surprisal first, and then generate association rules of good quality. Experimental results show that the surprisal-based pruning improves quality of association rules in question item response datasets significantly.

We have designed and fabricated an RF MEMS switch which has -50dB isolation at 2.4 GHz and 6 V operation voltage.

We successfully demonstrate that a thermally actuated reversible hydrogel, the poly N-Isopropylacrylamide (PNIPAAm), based clampers holds the intestines of a pig during the inchworm motion of microrobot. Although there are no direct relationship between hydro affinity and friction force, we found the significant friction force difference according to the surface condition change of PNIPAAm hydrogel. On the small intestine of a pig, a clamping mechanism was realized based on simple switching hydrophobic/hydrophilic surface conditions of PNIPAAm due to heating/cooling. In order to estimate response time of the clamper, the characteristic transition time of PNIPAAm film from hydrophilic to hydrophobic condition was investigated. Water contact angle (WCA) was monitored to normalize the transition time characteristics of PNIPAAm film in the course of time. From these results, we calculated the minimum heating time of the various thickness of PNIPAAm film to the clamping after its change to the hydrophobic condition. The minimum heating time was 15 seconds until 1 mm thickness of PNIPAAm film had enough friction force.

A concept of miniaturized and arrayed electron beam system using vertical interconnection was proposed and fabrication with interconnection using metal reflow was performed. The interconnection of electron beam array is very important because all single columns should be controlled individually to obtain a uniformity of electron beam array. In addition, the interconnection area should be reduced to make the size of a single column smaller. Therefore, a vertical interconnection method was proposed and the schematic of vertically interconnected monolithic microcolumn is shown. The other advantages of this vertical interconnection method are controllable columns and removal of interference between columns (Han, 2005).

A new method is proposed for generating if-then rules to predict peptide binding to class I MHC proteins, from the amino acid sequence of any protein with known binders and non-binders. In this paper, we present an approach based on artificial neural networks (ANN) and knowledge-based genetic algorithm (KBGA) to predict the binding of peptides to MHC class I molecules. Our method includes rule extraction from a trained neural network and then enhancing the extracted rules by genetic evolution. Experimental results show that the method could generate new rules for MHC class I binding peptides prediction.

Agent-based conference information management systems are proposed. Three different types of agent-based systems are introduced: single agent, multi agent and mobile agent. They manage the information intelligently and autonomously in Semantic Web using RDF and DAML.

How to obtain maximum generalization and fault-tolerance has been an important issue in designing a feedforward network. Research on rule-based neural networks suggests that generalization of a neural network is related to the directions of the pattern vectors encoded by hidden units, while fault-tolerance depends on the magnitudes of the weights. In this paper, a rule-based neural network is shown better than a standard neural network both in generalization and fault tolerance. In addition, a formal measure for evaluating network fault tolerance is introduced. >

We have achieved a high aspect ratio track-following microactuator (TFMA) which is capable of driving 2 /spl mu/g magnetic head for hard disk drive (HDD). It was fabricated on silicon on insulator (SOI) wafer with 20 /spl mu/m thick active silicon and 2 /spl mu/m thick thermally grown oxide and piggyback electrostatic principle was used for driving TFMA. The first vibration mode frequency of TFMA was 18.5 kHz which is enough for a recording density of higher than 10 Gb/in/sup 2/. Its displacement was 1.4 /spl mu/m when 15 V DC bias plus 15 V AC sinusoidal driving input was applied and its electrostatic force was 50 /spl mu/N when input voltage was 30 V.

To use poly-N-Isopropylacrylamide (PNIPAAm) as an actuator, we investigated its general characteristics such as swelling/deswelling ratio, response time and swelling force. Through out the variation, a change in volume of over 600% of PNIPAAm and a force generation of gram force order was obtained. Furthermore, we measured the significant change of friction caused by phase transition phenomena that is hydrophobic and hydrophilic. Surface condition that influences friction force can be reversed from swelling phase to deswelling phase by controlling the temperature of PNIPAAm. To verify the potential application of PNIPAAm using this characteristic, we compared its friction force under glass and small-intestine tissue of a pig. It was found that the level of friction differs significantly depending on phase change of PNIPAAm. Based on this knowledge, we could conclude that PNIPAAm can be applied to the stopping mechanism of in-body locomotion in order to replace the clamping mechanism of in body robot for locomotion on the gastrointestinal tract.

A silicon-based capacitive accelerometer with bulk silicon proof mass, polysilicon rib-style flexures, and detection circuits is fabricated and tested. A complementary metal oxide semiconductor (CMOS) compatible doping and annealing process for 2-µm-thick polysilicon used as a rib-style flexural beam is developed to optimize the trade-off between the mechanical properties and electrical requirements. According to the anisotropic etch simulation and experimental results, we designed a convex corner compensation pattern and fabricated the proof mass. The open-loop gain of the fabricated switched capacitor integrator (SCI) is more than four thousands, and the common mode range is from 0.8 V to 4.5 V. The fabricated accelerometer has sensitivity of 300 mV/g and capacitance change is 0.36 pF/g.

Named entities in the biomedical domain are often written using a Noun Phrase (NP) along with a coordinating conjunction such as ‘and’ and ‘or’. In addition, repeated words among named entity mentions are frequently omitted. It is often difficult to identify named entities. Although various Named Entity Recognition (NER) methods have tried to solve this problem, these methods can only deal with relatively simple elliptical patterns in coordinated NPs. We propose a new NER method for identifying non-elliptical entity mentions with simple or complex ellipses using linguistic rules and an entity mention dictionary.The GENIA and CRAFT corpora were used to evaluate the performance of the proposed system. The GENIA corpus was used to evaluate the performance of the system according to the quality of the dictionary. The GENIA corpus comprises 3434 non-elliptical entity mentions in 1585 coordinated NPs with ellipses. The system achieves 92.11% precision, 95.20% recall, and 93.63% F-score in identification of non-elliptical entity mentions in coordinated NPs. The accuracy of the system in resolving simple and complex ellipses is 94.54% and 91.95%, respectively. The CRAFT corpus was used to evaluate the performance of the system under realistic conditions. The system achieved 78.47% precision, 67.10% recall, and 72.34% F-score in coordinated NPs. The performance evaluations of the system show that it efficiently solves the problem caused by ellipses, and improves NER performance. The algorithm is implemented in PHP and the code can be downloaded from https://code.google.com/p/medtextmining/.