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The number of digital healthcare mobile applications in the market is exponentially increasing owing to the development of mobile networks and widespread usage of smartphones. However, only few of these applications have been adequately validated. Like many mobile applications, in general, the use of healthcare applications is considered safe; thus, developers and end users can easily exchange them in the marketplace. However, existing platforms are unsuitable for collecting reliable data for evaluating the effectiveness of the applications. Moreover, these platforms reflect only the perspectives of developers and experts, and not of end users. For instance, typical clinical trial data collection methods are not appropriate for participant-driven assessment of healthcare applications because of their complexity and high cost. Thus, we identified the need for a participant-driven data collection platform for end users that is interpretable, systematic, and sustainable, as a first step to validate the effectiveness of the applications. To collect reliable data in the participatory trial format, we defined distinct stages for data preparation, storage, and sharing. The interpretable data preparation consists of a protocol database system and semantic feature retrieval method that allow a person without professional knowledge to create a protocol. The systematic data storage stage includes calculation of the collected data reliability weight. For sustainable data collection, we integrated a weight method and a future reward distribution function. We validated the methods through statistical tests involving 718 human participants. The results of a validation experiment demonstrate that the compared methods differ significantly and prove that the choice of an appropriate method is essential for reliable data collection, to facilitate effectiveness validation of digital healthcare applications. Furthermore, we created a Web-based system for our pilot platform to collect reliable data in an integrated pipeline. We compared the platform features using existing clinical and pragmatic trial data collection platforms.

NPU Scheduler Tiling memory transactions between internal memories and external memories Communicating with AP Host and other processing units

Of late, deep neural networks have become ubiquitous in mobile applications. As mobile devices generally require immediate response while maintaining user privacy, the demand for on-device machine learning technology is on the increase. Nevertheless, mobile devices suffer from restricted hardware resources, whereas deep neural networks involve considerable computation and communication. Therefore, the implementation of a neural-network specialized hardware accelerator, generally called neural processing unit (NPU), has started to gain attention for the mobile application processor (AP). However, NPUs for commercial mobile AP face two challenges that are difficult to realize simultaneously: execution of a wide range of applications and efficient performance. In this paper, we propose a flexible but efficient NPU architecture for a Samsung flagship mobile system-on-chip (SoC). To implement an efficient NPU, we design an energy-efficient inner-product engine that utilizes the input feature map sparsity. We propose a re-configurable MAC array to enhance the flexibility of the proposed NPU, dynamic internal memory port assignment to maximize on-chip memory bandwidth utilization, and efficient architecture to support mixed-precision arithmetic. We implement the proposed NPU using the Samsung 5nm library. Our silicon measurement experiments demonstrate that the proposed NPU achieves 290.7 FPS and 13.6 TOPS/W, when executing an 8-bit quantized Inception-v3 model [1] with a single NPU core. In addition, we analyze the proposed zero-skipping architecture in detail. Finally, we present the findings and lessons learned when implementing the commercial mobile NPU and interesting avenues for future work.

On-device machine learning is critical for mobile products as it enables real-time applications (e.g. AI-powered camera applications), which need to be responsive, always available (i.e. do not require network connectivity) and privacy preserving. The platforms used in such situations have limited computing resources, power, and memory bandwidth. Enabling such on-device machine learning has triggered wide development of efficient neural-network accelerators that promise high energy and area efficiency compared to general-purpose processors, such as CPUs. The need to support a comprehensive range of neural networks has been important as well because the field of deep learning is evolving rapidly as depicted in Fig. 9.5.1. Recent work on neural-network accelerators has focused on improving energy efficiency, while obtaining high performance in order to meet the needs of real-time applications. For example, weightzero-skipping and pruning have been deployed in recent accelerators [2] –[7]. SIMD or systolic array-based accelerators [2] –[4], [6] provide flexibility to support various types of compute across a wide range of Deep Neural Network (DNN) models.

We present a healthcare remedy evaluation system, called CORUS, using blockchain-based crowdsourcing on a cloud computing platform. Efficacy of healthcare remedies such as functional foods and dietary supplements usually spreads by subjective word of mouth. Though regular clinical trials could be employed, it requires significant cost in time and budget. We expect crowdsourcing can be an effective and efficient alternative to the costly clinical trials to achieve objective evaluation on healthcare remedies. The blockchain technology can alleviate the problem of information quality in most of crowdsourcing systems. Properly designed reward distribution schemes can motivate voluntary participants to provide with credible information. The distributed replication of blockchains can increase the information credibility by prohibiting malicious forgery. We also utilize the Amazon cloud system to enhance availability and scalability. To our knowledge, CORUS is the first system to utilize crowdsourcing, blockchains, and cloud computing for healthcare remedy evaluation. It is available at https://corus.kaist.edu.

This paper present a 5.9 GHz dedicated short range communication (DSRC) transmitter for wireless vehicular communication that satisfies specification of IEEE 802.11p standard mask c. The proposed transmitter consists of programmable gain amplifier (PGA), up-conversion mixer, drive amplifier, and synthesizer. Passive mixer, push-pull local oscillator (LO) buffer, and intermodulation distortion (IMD) canceller are applied to achieve high linearity and low power consumption. The transmitter is designed and fabricated on CMOS 0.18 μm process. The total power consumption is 63 mA at 1.8 V. A phase noise of synthesizer is −109.4 dBc/Hz at 1MHz offset. The transmitter total noise figure (NF) and adjacent channel leakage ratio (ACLR) are 14.2 dB and − 53.6 dBc, respectively.

This paper presents 5–6GHz beamforming receiver with Q-factor calibrated vector modulator to reduce phase error and amplitude mismatch. Q-factor of vector modulator IQ network has to be 0.95–1.05 in 5–6GHz to get under ±3 ° phase error. Proposed Q-factor calibration circuit selects the best capacitance and resistance for proper Q-factor in 5–6GHz. Beamforming receiver prototype, which is implemented in 0.13μm CMOS, has 0.98–1.03 Q-factor in 5–6GHz. The prototype beamforming receiver rms phase error is maximum 1.5°, and amplitude mismatch is maximum 0.47dB. In addition, noise figure is 3.8–4.6dB at 5–6GHz.

The olfactory technology as an Information and Communication Technology provides immersive user experience and makes affective enhancement in digital contents technology area. Olfactory contents technology is divided into olfactory information recognition and olfactory contents representation. The olfactory recognition technology is likely to be applied to the medical field by detecting specific gas compounds in breath of patients and the air quality monitoring. In this paper, taking into consideration of the Internet of things concepts and characteristics of sensors, describes the multi-purpose connected electronic nose system. Attaching the multi-sensors is important to detect the various features, and system management for usability and connectivity has advantages for efficiency and accuracy of the electronic nose system as a sensor node.

Transmitting massive amounts of image and audio data acquired by Internet-of-Everything (IoE) devices to data center servers for intelligent recognition processes is impractical for energy reasons, requiring in-situ processing of such data. However, algorithms accelerated by previous recognition processors [1, 2] are limited to specific applications, therefore, each IoE device may require an application-specific accelerator. On the other hand, deep convolutional neural networks (CNNs) [3] are a promising machine-learning approach, showing state-of-the-art recognition accuracy in a wide variety of applications, including both image and audio recognition. This makes CNNs a suitable candidate for a universal recognition platform for IoE devices, as described in Fig. 14.6.1. Due to the computational complexity and significant memory requirements of CNNs, a microcontroller unit (MCU) typically used for IoE devices is incapable of producing a meaningful recognition result in an energy-efficient way. Hence, the implementation of an energy-efficient CNN processor is desired to realize intelligent IoE systems.

This paper proposes low power and high linearity up-down frequency converter for wireless telecommunication repeaters. A wireless telecommunication repeater is typically required high linearity and certain system dynamic range for automatic gain control (AGC). Furthermore, the demand of low power repeaters is increasing recently for green IT purpose. Capacitor cross-couple and threshold voltage decreasing techniques are applied to each sub building block in order to achieve the lowest power consumption and the highest linearity in a given technology and power supply voltage. Also, an ultra-low power wake-up receiver is implemented to control the shut-down when no user exits in the repeaters' connection range. One path of the converter is composed of a wideband down-converting mixer, programmable gain amplifiers (PGA), and a wideband up-converting mixer. The total power consumption is 150mA at 3.3V power supply. The output IP3s of the down-converting mixer and the up-converting mixer are 38dBm at 3dBm two tones output power and 25dBm at -10dBm two tones output power, respectively. The total dynamic gain range is more than 43dB with 1dB step resolution. Furthermore, 3mA wake-up receiver is designed and implemented. The up-down converter is fabricated on a 0.35um SiGe Bipolar CMOS technology.

This paper presents a new miniature haptic display to convey ample haptic information to a user of a handheld interface. There are buttons on interfaces or general electronic devices, but existing buttons provide haptic feedback of only one passive pattern to a user. Because humans perceive tactile and kinesthetic information simultaneously when they handle objects, the proposed actuator provides both sensations at once. It is able to generate various levels of kinesthetic sensations when pressing a button under diverse situations. Also, vibrotactile feedback can be delivered for exciting haptic effects with numerous patterns. Its performance was evaluated in accordance with the resistive force by changing the intensity of the input current. Experiments show that the proposed actuator has the ability to provide numerous haptic sensations for more realistic and complex haptic experiences.

Technology scaling and many-core design trends demand detailed information regarding the spatial temperature distribution, which is essential for dynamic thermal management [1,2]. The number of on-chip temperature sensors in high-performance processors is increasing, with state-of-the-art commercial processors embedding up to 44 on-chip sensors [3] and the number is likely to increase in the future (Fig. 14.7.1(a)). We observe two significant challenges in on-chip temperature sensing: 1) the increasing number of sensors, and 2) placing them in a regular manner (not solely on the potential hotspots). The number of sensors is mostly constrained by their area. Indeed, the sensor area is difficult to shrink since large delay lines or a BJT with a large ADC, and digital circuits are required to generate a proportional-to-absolute-temperature (PTAT) signal [2,5,6]. Many-core processor architectures give rise to the second challenge, namely, the hotspot locations within many-core processors are difficult to predict since we cannot determine the task allocation (and heat) profile at design time [2]. Consequently, an area-efficient dense thermal monitoring technique is desirable for next-generation processors.

A unified media application processor (UMAP) with a low-power mixed-mode feature extraction engine (FEE) is presented for 2D/3D image analysis/synthesis applications on handheld devices. UMAP supports not only graphics and vision for augmented reality (AR) but also 3D reconstruction and 3D display for 3D-view AR based on heterogeneous many-core platform. A frame-level 3-stage pipelined architecture enables real-time (50fps in VGA) performance in 3D-view AR, while a mixed-mode FEE dynamically saves active power by reconfiguring operation modes between analog and digital processing. Especially for low power operation in media processing, four pairs of analog current contention logics (CCL) are implemented in FEE. The implemented CCL does not require digital-to-analog or analog-to-digital converters (DAC/ADC) in interfacing digital and analog domains. It includes a diode-connected sensing stabilizer which reduces minimum sensing current. Therefore, average power consumed in CCL is reduced by 44.9%. In the implemented UMAP, the proposed FEE replaces the parallel processing core cluster in the analog processing mode, as a result, 96.5% of cluster power and 99.1% of target detection time are saved. The dynamic mode transition between analog and digital processing based on run-time tracking of region-of-interest (ROI) reduces system energy dissipation by up to 84.2% compared to the state-of-the-art embedded media processors.

In this paper, we designed the magnetically coupled resonators for wireless power transfer to mobile devices using field shaping technique. Power transfer to mobile devices is normally sensitive to variation of distance and alignment between transmitters and receivers. The magnetic field shaping technique, which is applied by On-line Electric Vehicle (OLEV) system, is considered to compensate the sensitivity, to reduce electromagnetic fields (EMF) around the receivers, and also to improve efficiency of power transfer [1]. We developed miniaturized coupled resonators to cover mobile devices, and enhanced coupling effect with modified formation of coupled resonators. Also, the coupled resonators are designed to receive power stably, less sensitive to variation of distance and alignment. We present measurement results with s-parameter value of the amount of power transferred.

Form factor and demand for low power consumption limit the transmission power of UHF mobile RFID readers. BoMR [1], a kind of booster for mobile RFID readers to extend the read range, was introduced and its performance was analyzed. But some practical issues such as collision and interference should be estimated for its widespread usage. In this paper, the collision, interference and performance of BoMRs are evaluated under multiple BoMR environments. Simulation model with DEVS formalism is presented and the results are summarized. Finally, the performances of LBT schemes are studied by simulation.

UHF RFID (Ultrahigh frequency radio frequency identification) is used in various application fields due to its advantages of cheap tag price and long reading range. Mobile RFID is a new technology that is expected to provide various services using RFID and cellular network. But the range of UHF RFID reader in cellular phone (mobile reader) is short. That is because the reader radiates low power of signal due to form factor and limited power supply. It is the obstacle to use it conveniently and to provide various services. In this paper, BoMR (a booster for mobile RFID readers) is designed and implemented to extend the range of a mobile reader. BoMR amplifies the signal of a granted reader and radiates it to tags. Consequently, the range is extended because the power of a tag's response signal is grown by amplified CW (continuous wave).

To augment tangible information into current social network systems (SNSs), this paper proposes an algorithm that generates force data from the user's hand gestures. The input modality defined in this paper is based on gesture information in the form of an acceleration profile in that at times it describes the current status of a user better than text-based content. For the physical representation of a motion update, corresponding force vectors in a Cartesian coordinate system are calculated with the proposed linear equation. Given the experimental results, it is predicted that the proposed physical logging and rendering scheme will provide a physical experience in mediated social connections.

Most data-intensive operations for multimedia applications such as image processing, vision, and 3D graphics require high external memory bandwidth. In augmented-reality (AR) processors [1], both 3D graphics and vision operations are required, so memory bandwidth becomes even more critical. In [1], however, memory bandwidth is not considered, floating-point processing is not supported, and there is no cache memory for texturing, which is a performance bottleneck of common graphics pipelines. In this work, a heterogeneous multimedia processor is presented to process various mobile multimedia applications in a single chip on Si-interposer for high memory bandwidth. The implemented processor has 4 key features: (1) A transceiver pool (TRx) that reconfigures strength of output drivers according to the channel loss for IC-stacking on Si-interposer, (2) A mode-configurable vector processing unit (MCVPU) for framelevel parallelism, (3) An energy-efficient unified filtering unit (UFU) with adaptive block selection (ABS) algorithm for memory-access-efficient texturing, and (4) a unified shader (US) with floating-point scalar processing elements (SPE) and partial special function units (PSFU) to enhance graphics processing performance and quality. With these techniques, we achieve 1.7× frame rate and 8× memory bandwidth improvement in full AR operation.

In this paper, the design of an armband type noncontact space input for human-machine interface is presented. Demand for a non-contact type input system has been increasing with the development of large-display technology. One of the non-contact type input system is a system based on gesture recognition. Unlike a glove type device, an armband device type does not constrain finger movements. We designed two different-types of armband space input systems for user interface. One is an arm band type space input system that uses arm movement and finger actions; the other is an armband type space input system by using arm movement and wrist snap actions.

In many ways, 3D graphics and vision processing are inverse operations. Graphics processing generates pixels from descriptors, while vision generates descriptors from pixels [1]. Since augmented reality (AR) requires both graphics and vision abilities (Fig. 18.6.1), we report a unified processor for graphics, vision, and pose estimation for marker tracking. To process both graphics and vision simultaneously, we use 4 key features: (1) 6-way VLIW datapath design of processing elements, (2) reconfigurable processing elements for graphics and vision modes, (3) a pixel arranger for vision processing that has the inverse characteristic of a graphics rasterizer, and (4) a dedicated pose-estimation engine to generate graphics control data from vision processing. Using these methods, we achieve 371.9GOPS/W for full operation in a VGA image and 0.89µW/fps for pose estimation.

This paper presents a self-sustaining system, and an effective method in enhancing overall energy efficiency. The proposed system consists of the two major nodes: a slave node, which contains the environment information (e.g., temperature, humidity, etc.); and a master node, which communicates with the slave nodes, and transmit the slave node's information to users. All slave nodes are under control of the master node. Each slave node uses two power sources: the piezoelectric power generator (PPG); and the continuous wave from the master node. The paper highlights the basic operational principle, each node's specifications, and experimental data for performance verification. The two nodes successfully communicate each other in a range of 3.3m (maximal range), where the user's computer is wired the master node.

In measuring the glucose density in the whole blood by handheld devices, the hematocrit is one of the most highly influencing factors. Since the hematocrit dependency should be appropriately controlled for accurate measurement of glucose density, information regarding hematocrit should be obtained at reasonable cost. This paper introduces an approach for hematocrit estimation from the transduced anodic current curves using support vector machine. These current curves are produced by glucose-oxidase reaction in the strip-type electrochemical biosensors which is commercially available. The support vector machine used in this paper was trained for regression with the target value of accurate glucose values measured by a hospital analysis system. This method can obtain an acceptable result that can be used to reduce the dependency of hematocrit in the measurement of glucose values in the whole blood with hand-held meters.

Recently, The researches of vehiclepsilas stability, controllability and comfortability are demanded because of increased usage of vehicle and mass transportation. The trend of vehicle is that the conventional vehicle accessories of mechanical link scheme are going to electronic module scheme connected by signal. The vehiclepsilas heavy mechanical steering linkages will be replaced to servo motors and signal cables. For example, the four wheel steering(4WS) vehicle driven by electric power has made by WIA corporation. That 4WS type vehicle has various advantages of driving. The vehicle can go leftward or rightward without turning and can turn in standing state. But past researches were proceeded based on mechanical system. To convert heavy mechanical accessories to electronic modules, the proper modeled signals and research data based on electronic system are needed. In this paper, the Ackerman geometry in mechanical system is applied to electronic independent four wheels steering system. And an analysis conducted about the real model 4WS vehicle was manufactured for using in factory to transport heavy loads by unmanned. Afterward, the effect of the converted presence of the Ackerman geometry in steering performance is simulated and examined.

Advancement in semiconductor technologies including CMOS and SiGe is enabling the commercialisation of devices that have increased switching speed, reduced power supply and increased circuit complexity. Proliferation of high-speed systems in both digital and mixed-signal applications is also driving the need for advanced noise suppression techniques. This paper describes a novel approach of using miniaturized electromagnetic bandgap structures. By leveraging on low shrinkage composite ceramics technology to increase the dielectric loading of the EBG structures, we have achieved significant improvement in the bandwidth and start frequency of more than 30% and 90%, respectively, when compared with conventional approaches.

In this paper, the effect of the Rician fading along the travel distance is studied, and practical measurement results are presented. Signal distortions have been can be detected as the travel distance between two antennas increases. The null points of an observed field are regarded as inter-symbol intersymbol interference from one RFID reader that will affect affects another neighboring RFID reader using an identical frequency channel. The results are shown and are discussed, compared.

A CMOS common gate LNA with high linearity over UHF mobile RFID bands is presented. A common gate configuration applied to design the proposed LNA overall leads to high linearity and wide band characteristics. Proposed LNA is fabricated with 0.35 mum (one poly, four metals) CMOS manufacturing technology. The proposed LNA shows 3.2 dB noise figure, 13.4 dB voltage gain with 1.4 dBm P1 dB.

In this paper, a channel allocation scheme for mediating UHF RFID bands is proposed. This scheme is designed for delivering a less-invasive channel area, a system capability enhancement, and intuitive data offering for overall strict the channel use and standardization UHF band (860 MHz-to-960 MHz). Several critical factors shall be discussed and simulated; thus, we can show the validity of this channel allocation proposal. Mostly, we focused on reducing collision effects among different types of UHF RFID reader systems within a single channel area and this shall be extended through some calculation and simulation works. Based on those works, we could obtain the appropriate solution for allocating each channel at less-invasion levels. This also will be discussed, presented and concluded with simulation results.

A multimodal interface can achieve more natural and effective human-computer interaction. In this paper, we present an isolated-word recognizer using a fusion of speech and natural visual gestures. The fusion of audio and visual signals can be carried out either at the class level or the feature level. Our system incorporates a fusion system at the feature level which supports 10 natural gestures. One of most difficult problems in feature level fusion is synchronization between audio and visual features. To solve this problem, we propose a modified time delay neural network (TDNN) architecture with a dedicated fusion layer and optimize parameters of this recognition model. Experimental results show that this system yields a performance improvement when compared to the performance of automatic speech recognition (ASR) under various signal-to-noise rate (SNR) conditions.

Mobile RFID system has been obtained much attention since modern trends in wireless communication technologies based on the Ubiquitous Networks. Among many components, Balun act as a converter which convert common mode signal to differential mode signal. There are two type of Balun, active type and passive type. Active Balun act good noise performance in entire communication system, but their linearity is limited by supply voltage. In this paper, we propose passive Balun implemented by IPD technology. Because Large power of TX CW compared to Tag reflecting signal leakages to RX signal path, so their linearity (especially 1 dB-compression point) is very important issue, and read range of Mobile RFID is not exceeding 2 m, so Tag reflected signal power is big compared to input thermal noise power. Besides we implement the Balun using IPD process, we can make entire system including RFID RF front-end chip and Balun into the Single chip. So we finally gained much smaller full-chip package.

Simple and new analysis method of phase noise requirements on a local oscillator (LO) for a RFID system is proposed. In general case, phase noise requirements are derived mathematically considering a reciprocal mixing with an interference signal. However, in RFID systems using the same oscillator for the transmitted signal and the LO, range correlation phenomenon effects the phase noise requirements. Thus we tried to derive new phase noise equation considering the range correlation effect on the residual phase noise in RFID system. Simulation results for IMF RFID system show that range correlation effect is a crucial factor in RFID system design.

In this paper, an ASK (amplitude shift keying) modulator with DGS (defected ground structure) is proposed for 900-MHz RFID (radio frequency identification) system. Proposed variable DGS resonator with a varactor diode will be able to adjust the resonance frequency to achieve the ASK modulation. The variable resonance characteristics can be obtained by controlling capacitance of varactor diode, placed on the defected ground. In order to clarify corresponding method, we manufactured RFID system board using variable DGS resonator and measured corresponding performance. As almost 93% of extracted data from modulation index characteristic is satisfied with both EPC class-1 Gen2 Type-B and Type-C standard protocols, we obtained stable tag response of RFID system.

The objective of this research is to propose and design a compact tactile display module and verify its performance in a pen-like haptic interface, particularly on the touch screen. A small, safe, silent and light tactile display module with low power dissipation has been built. Based on this module, we present the Ubi-Pen, a pen-like haptic interface providing texture and vibration stimuli. Preliminary evaluations indicate it can satisfactorily represent tactile patterns. We also evaluate its capacity to support GUI operations by producing a simple click-like feedback when buttons are pressed. In addition, it provides texture sensation when a user rubs an image displayed on a touch screen.

A fully integrated 900-MHz direct-conversion transceiver for mobile RFID system is presented. The transceiver consists of a low noise amplifier, a down-conversion mixer, a band pass filter, and programmable gain amplifier (PGA) for RX path; and a power amplifier, an up-conversion mixer, a low-pass filter, and a PGA for TX path. In addition, the fractional N PLL is integrated to cover different frequency standards for different nations. The transceiver meets the dense reader environment specifications.

In order to offer RFID services on mobile phones, the RFID reader must be embedded on the handset as a chip. However, the directional coupler, a ceramic passive component used in conventional handsets, of an RFID system using an identical Tx/Rx carrier frequency has a significant volume limitation compared to active components. This paper presents the directional coupler design for UHF RFID mobile reader using IPD (integrated passive device) process. The parallel-coupled line theory has been used for formulation of a T and pi-type coupler. Coupler with dimensions of 1.74times1.6, and 1.32times1.4 mm was assembled using the IPD process.

The objective of this research is to propose and design a compact tactile display module and verify its performance in a pen-like haptic interface. A small, safe, silent and light tactile display module with a low power dissipation has been built. Based on this module, we present the Ubi-Pen, a system providing texture and vibration stimuli. Preliminary evaluations indicate it can satisfactorily represent tactile patterns. We also investigate the optimal frequencies at which to present stimuli, and evaluate its capacity to support GUI operations by producing a simple click-like feedback when buttons are pressed

Multimodal interface is a human-centered interface. It is the point which is going to communicate with a computer by the system similar to communicating with man. It has the advantage which can choose suitable input-output method in the environment with restrictions in a specific interface. Also it can obtain a high reliability through the fusion of two or more input-output device. However, although there are many input-output modalities, the application using this is very little. Maybe, one of the reasons is the lack of a framework to support development of multimodal applications. This paper presents a design of multimodal interface framework (MMIF). The proposed multimodal interface framework enable rapid development of applications using a variety of modalities.

In this paper, the effects of radio frequency identification (RFID) reader interference are investigated in terms of the interrogation range. In order to evaluate RFID interference quantitatively, the signal-to-interference ratio (SIR) equation is initially derived, and the interrogation-reduction range ratio (IRRR) defined. IRRR is a function of the distance between a desired reader and an interfering reader. Co-channel interference (CCI) and adjacent-channel interference (ACI) instances of IRRR are simulated. Simulation results show that reader-reader distances achieving 0 % IRRR, indicating no interference between the two readers, are 1200 m and 35 m for the CCI and ACI cases, respectively. The IRRR factor is inversely proportional to the reader-reader distance in both cases. The simulation results were also verified by measurement results using an ETRI UHF RFID system. Measurement results were found to be in good agreement with the simulation results. It can be concluded that the present simulation results are reliable and applicable in analyses of more complex interfering problems in actual RFID system deployment instances.

A regulated low phase noise differential colpitts VCO (voltage controlled oscillator) for mobile RFID system is presented. The differential colpitts VCO meets the multiple- interrogator environment specifications. The VCO use a 0.35 mum technology and achieves tuning range 1.55 GHz - 2.053 GHz. Measuring 910 MHz frequency divider output, phase noise performance is -106 dBc/Hz and -135 dBc/Hz at 40 kHz and 1 MHz offset, respectively. 5-bit digital coarse-tuning and accumulation type MOS varactors allow for 28.2% tuning range, which is required to cover the LO frequency range of a UHF Mobile RFID system. Optimum design techniques ensure low VCO gain (< 45 MHz/V) for good interoperability with the frequency synthesizer. To the author' knowledge, this differential colpitts VCO achieves a figure of merit (FOM) of 1.93 dB at 2-GHz band.

This paper presents a pen-like haptic interface with a built-in compact tactile display module and a vibrating module. We describe evaluations verifying its performance and indicating that it can satisfactorily represent tactile patterns and provide vibrotactile feedback. Its applicability to combined force and tactile feedback display in a pen held haptic device is also investigated. Finally, we evaluate its capacity to support touch screen operations by providing tactile sensations when a user rubs against an image displayed on a monitor.

In this paper, we propose techniques converting odor information into digital data to provide representation, digital coding, and clustering of various odors for olfactory information communication. About forty emotional adjectives describing various kinds of odors are selected as expressional receptors. Each of the odors is expressed by a definite adjective. The odors expressed using emotional receptors are coded using a predetermined method for transmission. After being transmitted, the odor data is decoded using a fuzzy c-means (FCM) clustering algorithm. Since the odor data are expressed in 40 dimensions, a longer computing times and a larger size of memory are required for FCM algorithm. To solve these problems, the dimensions of the data are reduced by principal component analysis (PCA) before using the FCM algorithm.

A novel design approach is offered to attain circular polarization of the microstrip antenna feeds by unbalanced vertical feed-lines. Usually, diagonally balanced-line feeds with hybrid coupler are used to attain circular polarization. Here, Defected-ground structures (DGS) have been implemented under the unbalanced feed-lines to achieve circular polarization. Adopting DGS makes easy to tune antenna for circular polarization by varying the impedance of the feed-lines.

In this paper, a newly invented circulator for T/R switch of UHF radio-frequency identification (RFID) application is proposed to overcome TX-to-RX leakage problem. A microstrip coupled-line directional coupler is used for this passive circulator and the isolation characteristic is drastically improved not by complex method such as compensating phase velocity, but by considering both directional coupler itself and imperfect input impedance of the employed antenna. The measurement result of the proposed circulator using modified microstrip coupled-line directional coupler with employed antenna shows excellent TX-to-RX leakage suppression in the 860 MHz - 960 MHz, more than 45 dB enhancement at the center frequency compared to the conventional coupler. Experimental verification using RFID system is also performed to prove the validity of the proposed circulator.

In this paper, a non-uniform finite-difference time-domain (FDTD) method is incorporated with a design-sensitivity optimization technique to design a harmonic rejection microstrip low-pass filter (LPF) with defected ground. The proposed LPF features a defected ground plane to obtain high impedance on the microstrip line and perform a broad harmonic rejection. The design process initializes with the application of a developed FDTD solver to study the geometric parameters for filter analysis. The optimization technique modifies the parameter values and the structure is analyzed again until the performance meets the specified requirement

In this paper, we proposed a variable-impedance microstrip circuit using varactor diode as a control device. The proposed variable-impedance transmission line with a simple planar antenna can change the resonant frequency and the input impedance of antenna to achieve the DAM (direct antenna modulation). As an application of the variable-impedance microstrip circuit, we have implemented the ASK modulation of RF signal for the low-power consumption RFID applications. The experimental results show that a patch antenna with a resonant frequency of 2.45 GHz and a 30 MHz bandwidth can transmit a 1 Mbps digital modulated signal with the ultra low-power consumption

This paper presents a compact size microstrip patch antenna for L-band application. Overall /spl sim/75% size reduction has been achieved as compare to conventional microstrip antenna for same frequency band. We have designed dual fed microstrip patch antenna to obtain wide frequency band. Branch line coupler is used for 90/spl deg/ phase shift between two vertical feed and equal power coupling. Further, delay line has been designed between branch line coupler and microstrip patch for resonant frequency reduction. We can change the resonant frequency of a microstrip patch by changing the physical parameters of the delay line.

A novel compact Cascaded-E Inverted-F Slot (CEIFS) type microstrip antenna is proposed for quad bands, radio frequency telephone systems. This antenna design is particularly unique since it supports the new generation mobile phone handsets where multiband operation with minimum size is greatly desired. Slot lines are embedded in the antenna in cascaded-E and inverted-F shape parallel to the edge of the antenna length. This kind of new structure provides broad banding and multiple frequency bands. Detail of design criteria with respect to physical parameters is described. Radiation Patterns and impedance bandwidths are measured and shown.

We consider query slipping and its prevention in wireless sensor networks. The problem happens when a query propagating along a subscribe trajectory moves through a publish trajectory without obtaining the desired information, even though the two trajectories intersect geometrically. There follows resubmission of the query or initiation of another subscribe trajectory. Thus, query slipping results in considerable time delay and, in the worst case, looping in the trajectory or query flooding the network. We address the problem formally and suggest a solution. First, the area where nodes are distributed is logically partitioned into smaller grids, and a grid-based next-hop selection algorithm is proposed. The algorithm not only attempts to make the trajectory straight but also considers the nodal density of recipient nodes and the seamless grid-by-grid multicast. We show that publishing and subscribing using the algorithm eventually eliminates the possibility of slipping. It turns out that our approach dissipates less power at neighbor nodes, compared to a non grid-based method, such as greedy forwarding.

In a digital era, merging broadcasting and telecommunication is a general tendency worldwide. Specially, at a digital home, a digital TV can take a position as a core device by providing the integrated facilities which support broadcasting merged with the Internet. This paper presents a design of an integrated Web browser for these facilities, which supports digital data broadcasting and digital home networking as well as conventional Web browsing