Improved Distributed Algorithm to Optimize Coverage Control in Mobile Sensor Networks

This paper is originally the short version of my thesis or final project for my bachelor degree. The contents consist of what I’ve written in ICIUS 2010 and adapted idea of paper I wrote in 8^th IEEE ICNSC 2011. Adapted idea means that I adopted some algorithms from paper published in 8^th IEEE ICNSC 2011 and modified it to what I need in my thesis, in this case for limited range anisotropic sensor. This paper was planned to be published in a journal but I still don’t have any sponsor to publish it. Moreover, the way I wrote this paper is also not well-organized. Currently, I’m reorganizing the paper flow.

This paper is also one of the three researches I did during my spare time in last semester of my bachelor study.

As my thesis, this paper definitely has been presented in my final seminary on December, 8^th, 2010. The following is the abstract of this research:

In the deployment of mobile sensor networks, some agents may be initialized far away from region of interest and due to the sensor’s limited sensing of range, some sensors detect no information. Without any information, agents have no capability to move. As a result, some sensors may not able to participate in the coverage task. This paper describes how to solve this problem by implementing leader-following algorithm in a distributed control algorithm. An anisotropic mobile sensor model is considered. Then, an improved distributed coverage control algorithm is presented. In addition, energy and dynamic sensing of each mobile sensor is also considered. A power-aware distributed coverage control algorithm is also proposed to reduce energy consumption and optimize coverage ability. Moreover, it is assumed that each agent is equipped with omni-directional communication capability. A distributed control algorithm based on gradient descent is implemented to drive robots to the region of interest. Simulations illustrate the results.

The next actions for this research will be:

1. Considering the dynamic communication graph (still an idea)
2. 3 dimensions including odd environment (still an idea)
3. Non-convex environment (still an idea)

To see/download the paper click here.

Happy to discuss,

Best regards,

Risvan Dirza

Information-Driven Distributed Coverage Algorithms for Mobile Sensor Networks

This paper has been published in the 8^th IEEE International Conference on Networking, Sensing and Control (ICNSC) in Delft, The Netherland. This paper is one of the three researches I did during my spare time in last semester of my bachelor study.

I worked with Mas Iman who works in Prof. Sandra Hirce’s lab in TU Munich, Germany. The idea of this research is mainly to develop an algorithm for isolated agent(s) i.e. robot or other autonomous vehicles in a networks. We consider the communication capability as the weapon of the solution. More/less this paper has kind of relation with Finite Energy Coverage Control with Limited Range Anisotropic Sensor for Mobile Sensor Networks (extended).

Unfortunately, I couldn’t join the conference in Delft. Since, I just join a company where vacation is not allowed for the first year and they didn’t want to put it as business trip. However, doing a research is a fun. The following is the abstract of this research:

When mobile sensors are initially deployed, some sensors may be located far away from the region of interest and due to the sensor’s limited sensing of range, some sensors may not be able to participate in the coverage task. This paper proposes a new algorithm on the coverage problem for mobile sensor networks which guarantees all sensors to participate in the coverage task. The algorithm is a combination of the standard gradient-based coverage algorithm and leader following algorithm and is designed to maximize the joint detection probabilities of the events in the region of interest. First, leader sensors are selected based on the information which each sensor has gathered. The rest of the sensors will follow the leaders until they have sufficient information on the region of interest and then switch to the standard coverage algorithm. The proposed algorithm can be performed in a distributed manner. Moreover, the proposed algorithm could also improve the convergence speed of the coverage task. The results are validated through numerical simulations.

In my opinion, there are at least, 3 future actions of this paper that we can do:

1. Consider the dynamic communication graph (paper has been submitted)
2. Consider the optimization of communication cost (still no follow up)
3. Consider the energy consumption and sensing area (has been written in my thesis, but has not published yet)

Thus, ideas have been developed. Just need to conduct the research if there is a time. I guess I need a partner since I start working.

To see/download the paper click here.

Happy to discuss

Best Regards,

Risvan Dirza

High Throughput Direct Two Dimensional Discrete Cosine Transform (DCT) and Inverse DCT with No Transpositional Buffer and No Multiplier

There wasn’t so many courses, I took in the last semester of my bachelor study. That condition gave me, like, a lot of spare time. During that period, I did three researches simultaneously.  One of them was related to image processing.

I worked in team with Aidilla Pradini and Teuku Muhammad Roffi. Ideally, we had divided our part in the research. I mostly did the algorithm improvement, developed the objective and prove the mathematical equation. Aidilla mostly worked on the functional programming and RTL. While, Roffi mostly worked on the implementation to the FPGA. However, in fact, we did help each other in various areas.

This research was mostly conducted in Lab IC Design, PAU, ITB under supervisory of Dr. Trio Adiono.  The purpose of this research was to attend the LSI Design Contest in Okinawa. However, before being in Okinawa, we need to ensure that we pass the country round. Fortunately, we are selected as the main team that will represent Indonesia in the final round in Okinawa, Japan. Even I’ve joined an O&G company which of course has no intention of processing image, I got a really good opportunity at that time because the company allowed me to attend the final round as business trip (means the company will pay for everything).

The story went well until D-12 hours. Right 12 hours before our flight to Taipei (a flight to Okinawa will be transited via Taipei according the Airline Schedule), our campus cancelled the trip due to Fukushima Nuclear Power Plant tragedy in Japan. However, it wouldn’t be the “the end” of our research. The paper itself actually consists of three different researches (titles). One of those three titles had been accepted and will be presented in July 2011 (I’ll talk about it later).

Basically, the main point of the paper is to optimize all the main variables of an image processing to be as efficient as possible. The abstract is as follows:

An efficient algorithm and hardware implementation for a direct 2-D Discrete Cosine Transform (DCT) and inverse DCT is presented. A unique combination and sophisticated adaptation of algebraic integer encoding and butterfly structured algorithm is employed to achieve high troughput, bufferless, and multiplierless design. Eight 1-D 8 points DCT modules are employed each consists of so called modified 2-D algebraic integer encoding of a 1-D radix-8 DCT. The scaling and quantizer-dequantizer modules are also improved by approximation method. These algorithmic improvements result in a bufferless, multiplierless, zero memory usage, and direct processing 2-D DCT and inverse DCT designs. Simulations with MATLAB and ModelSim softwares prove that the proposed design have maintained PSNR and MSE values compared to that of conventional design. The design is further improved by employing a 5 stages pipelined implementation. The pipelined implementation results in a higher clock frequancy with high throughput. The system has a maximum frequancy of 210.084 MHz. Synthesis using Synopsis software shows that the design is 6.8 times faster in processing a token of 64 pixels compared to the conventional design. This improvement trades off with only 2.1 times increase in size compared to the conventional (refers to Level 1) design. Verification has been conducted using Altera DE2 FPGA Board and satisfying results have been obtained.

To see/download the paper, click here.

Happy to discuss,

Best Regards,

Risvan Dirza

Finite Energy Coverage Control with Limited Range Anisotropic Sensor for Mobile Sensor Networks (extended)

Following up the previous post of the preliminary study, here I try to post the complete paper titled Finite Energy Coverage Control with Limited Range Anisotropic Sensor for Mobile Sensor Networks.

In the middle of August 2010, I flight back to Indonesia and continue my study in electrical engineering department, Bandung Institute of Technology. Around 2 weeks after the arrival date, I met Prof. Bambang  R. Trilaksono that later become one of my thesis advisor/supervisor (The other one is Dr. Kusprasapta M.).

Even I only presented the preliminary study in Tokyo (which is only related to energy consideration), in fact, I’ve expanded my research to communication cost optimization. The expanded research has been written in a paper that published in International Conference on Intelligent and Unmanned System (ICIUS) 2010 sponsored by IEEE. This conference was conducted in Bali around October 2010. I was there to present the paper.

Presentation

Indonesian Reps

More/less the abstract of the paper is not much different than its preliminary study.

This paper presents the coverage control with mobile anisotropic sensor networks. Energy and communication cost of each mobile sensor are considered. Moreover, it is assumed that each agent is equipped with omni-directional communication capability. A distributed control algorithm based on gradient descent is also proposed to bring robots to the region of interest. Simulations illustrate the result.

To see/download the paper click here

Happy to discuss

Best Regards,

Risvan Dirza