Navigation systems providing route-guidance and traffic information are one of the most widely used driver-support systems these days. Most navigation systems are based on the map paradigm which plots the driving route in an abstracted version of a two-dimensional electronic map. Recently, a new navigation paradigm was introduced that is based on the augmented reality (AR) paradigm which displays the driving route by superimposing virtual objects on the real scene. These two paradigms have their own innate characteristics from the point of human cognition, and so complement each other rather than compete with each other. Regardless of the paradigm, the role of any navigation system is to support the driver in achieving his driving goals. The objective of this work is to investigate how these map and AR navigation paradigms impact the achievement of the driving goals: productivity and safety. We performed comparative experiments using a driving simulator and computers with 38 subjects. For the effects on productivity, driver's performance on three levels (control level, tactical level, and strategic level) of driving tasks was measured for each map and AR navigation condition. For the effects on safety, driver's situation awareness of safety-related events on the road was measured. To find how these navigation paradigms impose visual cognitive workload on driver, we tracked driver's eye movements. As a special factor of driving performance, route decision making at the complex decision points such as junction, overpass, and underpass was investigated additionally. Participant's subjective workload was assessed using the Driving Activity Load Index (DALI). Results indicated that there was little difference between the two navigation paradigms on driving performance. AR navigation attracted driver's visual attention more frequently than map navigation and then reduces awareness of and proper action for the safety-related events. AR navigation was faster and better to support route decision making at the complex decision points. According to the subjective workload assessment, AR navigation was visually and temporally more demanding.

In order to realize stable n-type characteristics of pentacene for applying to the organic complementary metal-oxide-semiconductor field-effect transistors (CMOS), we have fabricated pentacene based MOS diodes using ultra-thin Yb layer such as 0.5-3 nm between gate insulator and pentacene. From the results of capacitance-voltage (C-V) measurements, excellent n-type C-V characteristics of the devices with 1 and 2 nm-thick Yb were observed even though the devices were measured in air. These results suggested that the n-type semiconductor characteristics of pentacene are able to be improved by the thin Yb interfacial layer. Furthermore, the improved n-type characteristics of pentacene will enable the fabrication of flexible complementary logic circuits utilizing one kind organic semiconductor.

A novel NMOS Electrostatic Discharge (ESD) clamp circuit is proposed for a 0.35 µm Bipolar-CMOS-DMOS (BCD) process. The proposed ESD clamp has a non-snapback characteristic because of gate-coupled effect. This proposed ESD clamp circuit is developed without additional components made possible by replacing a capacitor with an isolated parasitic capacitor. The result of the proposed ESD clamp circuit is measured by 100 ns Transmission Line Pulse (TLP) system. From the measurement, it was observed that the proposed ESD clamp has approximately 40% lower triggering voltage compared to the conventional gate-grounded NMOS ESD clamp. This is achieved without degradation of the other ESD design key parameter. The proposed ESD clamp also has high robustness characteristics compared to the conventional RC-triggered NMOS ESD clamp circuit.

Recently, the 3-dimensional (3-D) vertical Floating Gate (FG) type NAND flash memory cell arrays with the Extended Sidewall Control Gate (ESCG) was proposed [7]. Using this novel structure, we successfully implemented superior program speed, read current, and less interference characteristics, by the high Control Gate (CG) coupling ratio with less interference capacitance and highly electrical inverted S/D technique. However, the process stability of the ESCG structure has not been sufficiently confirmed such as the variations of the physical dimensions. In this paper, we intensively investigated the electrical dependency according to the physical dimensions of ESCG, such as the line and spacing of ESCG and the thickness of barrier oxide. Using the 2-dimentional (2-D) TCAD simulations, we compared the basic characteristics of the FG type flash cell operation, in the aspect of program speed, read current, and interference effect. Finally, we check the process window and suggest the optimum target of the ESCG structure for reliable flash cell operation. From above all, we confirmed that this 3-dimensional vertical FG NAND flash memory cell arrays using the ESCG structure is the most attractive candidate for terabit 3-D vertical NAND flash cell array.

In this paper, a 24 GHz frequency source for low phase noise is presented in a 0.18 µm CMOS process. The 24 GHz frequency source chip is composed of a 12 GHz voltage controlled oscillator (VCO) and a 24 GHz balanced frequency doubler with class B gate bias. Compared to a conventional complementary VCO, the proposed 12 GHz VCO has phase noise improvement by using resistor current sources and substituting the nMOS cross-coupled pair in the conventional complementary VCO for a gm-boosted nMOS differential Colpitts pair. The measured phase noise and fundamental frequency suppression are -107.17 dBc/Hz at a 1 MHz offset frequency and -20.95 dB at 23.19 GHz frequency, respectively. The measured frequency tuning range is from 23.19 GHz to 24.76 GHz drawing 2.72 mA at a supply voltage of 1.8 V not including an output buffer.

We present a design optimization method of H-plane waveguide components, based on the level set method with the finite element method. In this paper, we propose a new formulation for the improvement of a level set function, which describes shape, location, and connectivity of dielectric in a design region. Employing the optimization procedure, we demonstrate that optimized structures of an H-plane waveguide filter and T-junction are obtained from an initial structure composed of several circular blocks of dielectric.

In this paper, we report the fabrication and device characteristics of InP/InGaAs double heterojunction bipolar transistors (DHBTs) with buried SiO2 wires. The SiO2 wires were buried in the collector and subcollector layers by metalorganic chemical vapor deposition toward reduction of the base-collector capacitance under the base electrode. A current gain of 22 was obtained at an emitter current density of 1.25 MA/cm2 for a DHBT with an emitter width of 400 nm. The DC characteristics of DHBTs with buried SiO2 wires were the same as those of DHBTs without buried SiO2 wires on the same substrate. A current gain cutoff frequency (fT) of 213 GHz and a maximum oscillation frequency (fmax) of 100 GHz were obtained at an emitter current density of 725 kA/cm2.

We propose the collective electron tunneling model in the electron injection process between the Nano Dots (NDs) and the two-dimensional electron gas (2DEG). We report the collective motion of electrons between the 2DEG and the NDs based on the measurement of the Si-ND floating gate structure in the previous studies. However, the origin of this collective motion has not been revealed yet. We evaluate the proposed tunneling model by the model calculation. We reveal that our proposed model reproduces the collective motion of electrons. The insight obtained by our model shows new viewpoints for designing future nano-electronic devices.

This letter proposes a novel decision fusion algorithm for cooperative spectrum sensing in cognitive radio sensor networks where a reinforcement learning algorithm is utilized at the fusion center to estimate the sensing performance of local spectrum sensing nodes. The estimates are then used to determine the weights of local decisions for the final decision making process that is based on the Chair-Vashney optimal decision fusion rule. Simulation results show that the sensing accuracy of the proposed scheme is comparable to that of the Chair-Vashney optimal decision fusion based scheme even though it does not require any knowledge of prior probabilities and local sensing performance of spectrum sensing nodes.

We find necessary and sufficient conditions for the (shifted) oversampling expansions to hold in wavelet subspaces. In particular, we characterize scaling functions with the (shifted) oversampling property. We also obtain L2 and L∞ norm estimates for the truncation and aliasing errors of the oversampling expansion.

In this letter, a new terrain type classifier is proposed for polarimetric Synthetic Aperture Radar (Pol-SAR) images. This classifier uses the binary tree structure. The homogenous and inhomogeneous areas are first classified by the support vector machine (SVM) classifier based on the texture features extracted from the span image. Then the homogenous and inhomogeneous areas are, respectively, classified by the traditional Wishart classifier and the SVM classifier based on the texture features. Using a NASA/JPL AIRSAR image, the authors achieve the classification accuracy of up to 98%, demonstrating the effectiveness of the proposed method.

Many kinds of microstrip array antennas have been developed in the millimeter-wave band. In order to avoid feeding loss and the decrease of antenna gain by beam shift due to frequency changes, center-fed array antennas are advantageous. In this case, the element spacing around the feeding circuit of the transition from the waveguide to two microstrip lines is larger than one wavelength. Therefore, the sidelobe level grows significantly. In order to suppress the sidelobe level, we propose transitions with slot radiators. Moreover, any polarization angles can be achieved by changing the slot angle. A wide variety from 1.5% to 70% of slot radiator coupling powers can be achieved. To investigate the performance of the proposed transition, 10, 22 and 30-element center-fed microstrip comb-line antennas with the proposed transition were developed at 76.5 GHz, and measured performance was evaluated in the millimeter-wave band.

We provide a BER analysis of the well-known rotation code, which has been applied to various transmission schemes, such as coordinate-interleaved design (CID) for space-time block codes and trans-modulation or constellation rearrangement for a cooperative relay system. An upper bound on the BER of the rotation code under a fading channel is derived. It turns out to be much tighter than the existing one, which relies on the Chernoff bound. More specifically, the proposed bound is virtually identical to simulation result when Eb/No is larger than 4 dB.

In this letter, a multiuser cooperative network with multiple relays is introduced, and two decode-and-forward (DF) cooperation schemes are proposed aiming at outage-optimal and fair user scheduling, respectively. The outage probability and asymptotic expressions of symbol error probability (SEP) are derived to evaluate these two schemes. Analysis and simulations show that both schemes can achieve full diversity order, which is the combination of cooperative diversity and multiuser diversity.

In order to reduce PtSi Schottky barrier height (SBH) for electron, we investigated modulation of PtSi work function by alloying with low work function metal, such as Hf (3.9 eV) and Yb (2.7 eV). Pt (10-20 nm)/Hf, Yb (0-10 nm)/n-Si(100) stacked structures were in-situ deposited at room temperature by RF magnetron sputtering method. In case of PtxHf1 - xSi formed at 400/60 min annealing in N2, SBH for electron was reduced from 0.85 eV to 0.53 eV with Hf thickness without increase of sheet resistance. Yb incorporation also affected the SBH modulation, however, the sheet resistance increased with increase of Yb thickness.

Multiple antenna is introduced into spectrum sensing in cognitive radios recently. However, conventional multiple antenna spectrum sensing schemes exploited only space diversity. In this paper, we propose a new multiple antenna sensing scheme based on space and time diversity (MASS-BSTD). First, the primary user signal to be sensed is over-sampled at each antenna, and signal samples collected at the same time instant from different antennas are stacked into a column vector. Second, each column vector is utilized to estimate space correlation matrix that exploits space diversity, and two consecutive column vectors are utilized to estimate time correlation matrix that exploits time diversity. Third, the estimated space correlation matrix and time correlation matrix are combined and analyzed using eigenvalue decomposition to reduce information redundancy of signals from multiple antennas. Lastly, the derived eigenvalues are utilized to construct the test statistic and sense the presence of the primary user signal. Since the proposed MASS-BSTD exploits both space diversity and time diversity, it achieves performance gain over the counterparts that only exploit space diversity. Furthermore, the proposed MASS-BSTD requires no prior information on the primary user, the channel between primary user transmitter and secondary user receiver, and is robust to noise uncertainty. Theoretical analysis and simulation results show that the proposed MASS-BSTD can sense the presence of primary user signal reliably.

We have investigated the effect of deoxyribonucleic acid (DNA) adsorption on a graphene field-effect-transistor (FET) device. We have used graphene which is grown on a Ni substrate by chemical vapour deposition. The Raman spectra of our graphene indicate its high quality, and also show that it consists of only a few layers. The current-voltage characteristics of our bare graphene strip FET show a hole conduction behavior, and the gate sensitivity of 0.0034 µA/V, which is reasonable with the size of the strip (510 µm2). After the adsorption of 30 base pairs single-stranded poly (dT) DNA molecules, the conductance and gate operation of the graphene FET exhibit almost 11% and 18% decrease from those of the bare graphene FET device. The observed change may suggest a large sensitivity for a small enough (nm size) graphene strip with larger semiconducting property.

Vulnerabilities in web applications expose computer networks to security threats. For example, attackers use a large number of normal user websites as hopping sites, which are illegally operated using malware distributed by abusing vulnerabilities in web applications on these websites, for attacking other websites and user terminals. Thus, the security threats, resulting from vulnerabilities in web applications prevent service providers from constructing secure networking environments. To protect websites from attacks based on the vulnerabilities of web applications, security vendors and service providers collect attack information using web honeypots, which masquerade as vulnerable systems. To collect all accesses resulting from attacks that include further network attacks by malware, such as downloaders, vendors and providers use high-interaction web honeypots, which are composed of vulnerable systems with surveillance functions. However, conventional high-interaction web honeypots can collect only limited information and malware from attacks, whose paths in the destination URLs do not match the path structure of the web honeypot since these attacks are failures. To solve this problem, we propose a scheme in which the destination URLs of these attacks are corrected by determining the correct path from the path structure of the web honeypot. Our Internet investigation revealed that 97% of attacks are failures. However, we confirmed that approximately 50% of these attacks will succeed with our proposed scheme. We can use much more information with this scheme to protect websites than with conventional high-interaction web honeypots because we can collect complete information and malware from these attacks.

We investigated the effects of various field plate and buried gate structures on the DC and small signal characteristics of 4H-silicon carbide (SiC) metal-semiconductor field-effect transistors (MESFETs). In comparison with the source-connected field plate, the gate-connected field plate exhibited superior frequency response while having similar DC characteristics. In order to further enhance the output power, dual field plates were employed in conjunction with a buried gate structure.

The excessive memory access required to perform motion compensation when decoding compressed video is one of the main limitations in improving the performance of an H.264/AVC decoder. This paper proposes an H.264/AVC decoder that employs three techniques to reduce external memory access events: efficient distribution of reference frame data, on-chip cache memory, and frame memory recompression. The distribution of reference frame data is optimized to reduce the number of row activations during SDRAM access. The novel cache organization is proposed to simplify tag comparisons and ease the access to consecutive 4×4 blocks. A recompression algorithm is modified to improve compression efficiency by using unused storage space in neighboring blocks as well as the correlation with the neighboring pixels stored in the cache. Experimental results show that the three techniques together reduce external memory access time by an average of 90%, which is 16% better than the improvements achieved by previous work. Efficiency of the frame memory recompression algorithm is improved with a 32×32 cache, resulting in a PSNR improvement of 0.371 dB. The H.264/AVC decoder with the three techniques is fabricated and implemented as an ASIC using 0.18 µm technology.