Filbert H. Juwono

Bio: Filbert H. Juwono is an academic researcher from Curtin University. The author has contributed to research in topics: Orthogonal frequency-division multiplexing & Computer science. The author has an hindex of 9, co-authored 52 publications receiving 304 citations. Previous affiliations of Filbert H. Juwono include University of Western Australia & University of Indonesia.

A Novel Differentially Fed Compact Dual-Band Implantable Antenna for Biotelemetry Applications

Abstract: A novel differentially fed dual-band planar antenna operating at the Medical Implant Communication Service band (402–405 MHz) and the Industrial, Scientific, and Medical band (2400–2480 MHz) is presented. The measured 10-dB differential reflection coefficient bandwidth is 389–419 MHz (7.4%) at the lower band and 2395–2563 MHz (6.6%) at the upper band, respectively. With the use of symmetric meandered strip and shorting pin, a differentially fed compact dual-band design is obtained, where the volume of the prototype is only 642.62 mm3 (22 mm × 23 mm × 1.27 mm). Due to its small size and dual-band operation, the proposed antenna can be connected to differential circuits in implantable biotelemetric devices.

Deep Clipping for Impulsive Noise Mitigation in OFDM-Based Power-Line Communications

Abstract: Nonlinear preprocessors, including clipping, blanking, and joint blanking/clipping have been proposed to be employed in orthogonal frequency-division multiplexing systems for mitigating the impulsive noise in power-line communications. In this paper, we propose using a new variant of nonlinear preprocessor, namely, deep clipping, to mitigate the impulsive noise. In contrast to clipping, blanking, and joint blanking/clipping, where one or two thresholds is used to detect if the impulsive noise occurs, and if the impulsive noise occurs how to handle it, deep clipping is characterized by two alternative parameters, namely, a threshold and a depth factor. By optimizing the two parameters, we find that deep clipping achieves better signal-to-noise ratio (SNR) performance than clipping, blanking, and joint blanking/clipping. In addition, we present a mathematical expression for deep clipping and show that the SNR expressions regarding conventional clipping, blanking, and joint blanking/clipping can be easily obtained by using our analytical methods.

Multi-Features Capacitive Hand Gesture Recognition Sensor: A Machine Learning Approach

Abstract: Gesture recognition technology enables machines to understand human gestures. The technology is considered as a key enabler for gaming and virtual reality applications. In this paper, we propose an effective, low-cost capacitive sensor device to recognize hand gestures. In particular, we designed a prototype of a wearable capacitive sensor unit to capture the capacitance values from the electrodes placed on finger phalanges. The sensor captures finger capacitance values. Each gesture has specific finger capacitance values. We applied a running median filter to the output of the sensor and extracted 15 features for gesture classification training and testing tasks. Subsequently, various analyses were performed to provide more insights into the sensing data. We applied and compared two machine learning algorithms: Error Correction Output Code Support Vector Machines (ECOC-SVM) and ${K}$ -Nearest Neighbour (KNN) classifiers. The training and testing recognition rates were observed for both intra-participant and inter-participant data sets. Further, we introduced a feature compression approach derived from correlation analysis to reduce the complexity of the machine learning algorithms. Using cross validation, we achieved a classification rate of approximately 99% for intra-participant data. We achieved a lower recognition rate of 97% (average cross validation testing) for compressed feature data set using both machine learning approaches. For the inter-participant data, the recognition rate was 99% (normalized feature data) using KNN and 97% using ECOC-SVM. The research findings show that our recognition system is competitive and has an immense potential for further study.

Linear Combining of Nonlinear Preprocessors for OFDM-Based Power-Line Communications

Abstract: Nonlinear preprocessors, including conventional clipping, blanking, joint blanking/clipping, and deep clipping, have been employed to mitigate the impulsive noise in orthogonal frequency division multiplexing-based power-line communications. Those nonlinear preprocessors are characterized by one or two thresholds, which are optimized to achieve an optimum output signal-to-noise ratio (SNR). In this paper, we aim to further improve the output SNR by linearly combining two nonlinear preprocessors. Both analytical and simulation results show that the proposed method yields better output SNR and symbol/bit error rate performance than the individual ones.

On the Performance of Blanking Nonlinearity in Real-Valued OFDM-Based PLC

Abstract: To mitigate the impulsive noise in orthogonal frequency-division multiplexing (OFDM)-based power-line communications (PLC), a blanker can be employed at the receiver. In the literature, the performance of the blanker has been discussed and analyzed thoroughly. However, the analysis was limited only to passband OFDM PLC systems with complex-valued baseband representation. This paper aims to derive a mathematical expression of the output signal-to-noise ratio (SNR) of a blanker in baseband OFDM-based PLC, which are real-valued and used in some PLC standards. We also analyze the performance of separate real/imaginary blanking, instead of the traditional amplitude blanking, in passband OFDM-based PLC systems. It will be shown that the performance of amplitude blanking is similar to separate real/imaginary blanking in high signal-to-impulsive-noise ratio (SINR) values. However, when the SINR is low, the performance of amplitude blanking is better than the separate real/imaginary blanking. The difference is about 1 dB for ${SINR = -10}$ dB and 1.5 dB for ${SINR = -30}$ dB when signal-to-background-noise ratio, ${SBNR=25}$ dB and impulsive noise probability ${p=0.01}$ .

An Introduction to Game Theory

Abstract: This chapter is devoted to a more detailed examination of game theory. Game theory is an important tool for analyzing strategic behavior, is concerned with how individuals make decisions when they recognize that their actions affect, and are affected by, the actions of other individuals or groups. Strategic behavior recognizes that the decision-making process is frequently mutually interdependent. Game theory is the study of the strategic behavior involving the interaction of two or more individuals, teams, or firms, usually referred to as players. Two game theoretic scenarios were examined in this chapter: Simultaneous-move and multi-stage games. In simultaneous-move games the players effectively move at the same time. A normal-form game summarizes the players, possible strategies and payoffs from alternative strategies in a simultaneous-move game. Simultaneous-move games may be either noncooperative or cooperative. In contrast to noncooperative games, players of cooperative games engage in collusive behavior. A Nash equilibrium, which is a solution to a problem in game theory, occurs when the players’ payoffs cannot be improved by changing strategies. Simultaneous-move games may be either one-shot or repeated games. One-shot games are played only once. Repeated games are games that are played more than once. Infinitely-repeated games are played over and over again without end. Finitely-repeated games are played a limited number of times. Finitely-repeated games have certain or uncertain ends.

OFDM for Optical Communications

Abstract: Orthogonal frequency division multiplexing (OFDM) is a modulation technique which is now used in most new and emerging broadband wired and wireless communication systems because it is an effective solution to intersymbol interference caused by a dispersive channel. Very recently a number of researchers have shown that OFDM is also a promising technology for optical communications. This paper gives a tutorial overview of OFDM highlighting the aspects that are likely to be important in optical applications. To achieve good performance in optical systems OFDM must be adapted in various ways. The constraints imposed by single mode optical fiber, multimode optical fiber and optical wireless are discussed and the new forms of optical OFDM which have been developed are outlined. The main drawbacks of OFDM are its high peak to average power ratio and its sensitivity to phase noise and frequency offset. The impairments that these cause are described and their implications for optical systems discussed.

Scalp-Implantable Antenna Systems for Intracranial Pressure Monitoring

Abstract: This communication proposes miniaturized implantable antenna systems for biomedical applications, specifically for scalp implantation. The proposed designs exhibit dual-band characteristics on the industrial, scientific, and medical bands (i.e., 915 and 2450 MHz) with small volumes: 344 mm3 (System A) and 406 mm3 (System B). Each system is integrated with the microelectronic components and a battery. The key feature of the proposed implantable antenna is its small volume ( $8 \times 6 \times 0.5$ = 24 mm3) with a slotless and a vialess ground plane, thereby reducing design complexity. Moreover, the structure exhibits satisfactory peak gain values of −28.5 and −22.8 dBi at a lower and higher resonant band, respectively. Simulations using the finite-element method and finite-difference time domain are performed to evaluate the implantable systems. For validation, measurements are carried out in a saline solution. The antenna offers a good agreement between the measured and simulation results. In addition, a link budget is calculated to analyze the data transmission range.

An Implantable and Conformal Antenna for Wireless Capsule Endoscopy

Abstract: This letter proposes an implantable antenna with ultrawide bandwidth operating in the medical device radio communications service band (401–406 MHz) for the wireless capsule endoscopy (WCE). The simulation and experimental results show the proposed antenna has a good performance in terms of the return loss and hence the bandwidth from 284 to 825 MHz. The maximum realized gain of this antenna is –31.5 dBi at 403 MHz. The maximum simulated input power is <1.7 mW in order to satisfy the specific absorption rate (SAR) regulations in the IEEE standard. The tolerance of the antenna owing to bendability and different WCE shell thicknesses is investigated. These indicate that the proposed antenna is a good candidate for the WCE.

Impulsive Noise Mitigation in Underwater Acoustic OFDM Systems

Abstract: Mitigation of impulsive noise has been extensively studied in wireline, wireless radio, and powerline communication systems. However, its study in underwater acoustic (UWA) systems is quite limited. This paper considers impulsive noise mitigation for underwater orthogonal frequency-division multiplexing (OFDM) systems, where the system performance is severely impacted by the channel Doppler effect. We propose a practical approach based on a least squares formulation: First, the positions of impulsive noise are determined in the time domain based on the signal amplitude, and second, impulsive noise samples are jointly estimated with the Doppler shift based on the measurements of the OFDM null subcarriers. Based on the available channel estimate and tentative data symbol decisions, an iterative receiver is further developed. Data sets have been acquired in a recent sea experiment near Kaohsiung city, Taiwan, in May 2013. Performance results based on extensive simulations and collected data sets demonstrate that the proposed receivers effectively mitigate impulsive noise for UWA OFDM systems.