Pornavalai, Chotipat
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Pornavalai, Chotipat
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Pomavalai, Chotipat
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chotipat.po@kmitl.ac.th
24 results
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Item type:Publication, Fuzzy-spray: Efficient routing in delay tolerant ad-hoc network based on fuzzy decision mechanism(2009-01-01); Chakraborty, GoutamDelay Tolerant Network (DTN) is a sparse and intermittently connected mobile wireless network where reliable communication and end-to-end connectivity cannot be assured. In DTN, a node delivers messages to the destination using store and forward scheme. Messages are copied and transferred to multiple relay-nodes in order to increase the opportunity for that message to reach the intended destination. Contact is the time duration for which two or more mobile nodes encounter each other within their radio transmission ranges, and are able to transfer messages. Due to arbitrary node movement, contact time will be varied, and is unlikely to be predictable. In this paper, we propose a fuzzy decision mechanism we called "fuzzy-spray", to improve the routing and packet transfer efficiency in DTN environment. Fuzzy-spray can reduce overall latency in DTN by intelligently selecting appropriate messages to send to the relay-node during its next contact time. It uses fuzzy logic to prioritize messages that are stored in the buffer, based only on local parameters from each message, namely forward transmission count and message size. There is no need to know a priori information about network such as node mobility model, or node-distribution across the deployed area. The simulation results show that fuzzy-spray has the best performance in terms of overall speed of delivery, and lowest average message delay compared with other existing algorithms. ©2009 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Dynamic multicast routing in advance resource reservation environment(2000-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Optimal routing for dynamic multipoint connection(1999-01-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Scanning behavior for efficient energy consumption in delay tolerant network(2017-11-03) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Designing of policy-based negotiation protocol on MANET(2006-12-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A Practical Circuit of Cyclic Chirp Spread Spectrum Modulation for Long Range Communication(2022-01-01); ; ; Various technologies have been utilized in long range communication to satisfy increasing usage of the internet of things in a wide large area. Recently, a modulating technique called cyclic chirp spread spectrum (CSS) modulation has attracted attention due to its low power usage and long-range coverage. However, a cyclic CSS circuit is complex to build. Hence, the objective of the work is to propose a practical circuit of cyclic CSS modulation. The proposed circuit is designed to complicated-free creation. To prove that the presented circuit is pragmatic, a simulation test is performed. The simulation results have illustrated that the designed circuit well generates a chirp modulating signal. Also, the proposed circuit is flexibly configurable. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A Simplified Analog Implementation of Cyclic Shift Chirp Encoding and Decoding for LoRa Communications(2026-06-01); Currently, LoRa wireless communication technology has become widely adopted in IoT systems due to its long-range capability and low power consumption. However, LoRa is a technology developed by Semtech, which does not disclose the details of the Cyclic Shift Chirp encoding process, a core component of LoRa signals. This lack of transparency prevents users from accessing the physical-layer structure of the signal or freely customizing key parameters such as bandwidth and spreading factor. Although such customization can enhance system flexibility, there is currently no officially disclosed method to achieve it. This research proposes a Cyclic Shift Chirp encoder/decoder circuit built from basic analog components, including adders, subtractors, comparators, and ramp generators, based on a Pulse Width Modulation (PWM) principle. This approach enables researchers and developers to generate LoRa-like signals independently and customize various parameters without introducing limitations. Moreover, the proposed circuit is simple, low-cost, and easy to understand, making it suitable for advanced research, educational experiments, and the design of communication systems that require high flexibility at the LoRa PHY layer. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Experimental performance evaluation of LoRaWAN: A case study in Bangkok(2017-09-05); The Internet of Things (IoT) is a vision which real-world objects are part of the internet. Every object is uniquely identified, and accessible to the network. There are various types of communication protocol for connect the device to the Internet. One of them is a Low Power Wide Area Network (LPWAN) which is a novel technology use to implement IoT applications. There are many platforms of LPWAN such as NB-IoT, LoRaWAN. In this paper, the experimental performance evaluation of LoRaWAN over a real environment in Bangkok, Thailand is presented. From these experimental results, the communication ranges in both an outdoor and an indoor environment are limited. Hence, the IoT application with LoRaWAN technology can be reliable in limited of communication ranges. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, EORL: Energy Optimization via Reinforcement Learning in Software-Defined Wireless Sensor Networks(2024-01-01); ; Tanessakulwattana, SarayootA wireless sensor network is a collection of sensors placed in a particular area to collect and transmit data to the base station or sink. They usually have batteries as the primary power sources. If they work for a long time, their energy will be exhausted. Replacing the battery may not be cost-effective compared to developing an algorithm that optimizes energy efficiency to extend the network lifetime. This work optimizes the energy consumption of wireless sensor networks by adaptively selecting an optimal routing path in a Software-defined Wireless Sensor Networks (SDWSN) environment. A concept of the energy balance among nodes according to the current network status by the SDWSN controller using Reinforcement Learning (RL) is introduced. We propose energy optimization via reinforcement learning (EORL) for SDWSN using a minimum energy reward function and state design that considers energy consumption. The EORL algorithm then identifies the node that requires attention and selects the most energy-efficient path for that node. The performance of the EORL shows that it has a more extended network lifetime compared with other RL solutions. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A policy based negotiation protocol for services agreement in mobile(2005-12-01); Varakulsiripunth, RuttikornIn this paper, we have proposed an approach of negotiation protocol for services agreement between two wireless nodes in ad hoc networks. Protocol principles are based on peculiarities of mobile nodes and mobile users on MANET, i.e., user autonomy, node functionality and resource management. Mobile users can use this negotiation protocol for defining its network functions in MANET based on their policy. Service level agreements between two wireless nodes can be renegotiated depending on current user's application requirements and available resources. Protocol is designed to be able to negotiate on many parameters such as route, link bandwidth or QoS. We also present a scenario in MANET to show the effectiveness of our proposed protocol. © 2005 IEEE.1