In this letter, we present a wireless sensor network for monitoring the maturity stage of fruit. ... more In this letter, we present a wireless sensor network for monitoring the maturity stage of fruit. A dual-polari-zation coupled patch sensor, which is robust to environmental changes, was designed to operate at 2.45 GHz. It was attached to a Durian fruit for a period of days to measure the magnitude of mutual coupling corre-sponding mainly to the starch concentration of its pulp. Signal was transmitted from a sensor node, via tree nodes, to a master node that displays the variations occurring in the period. The maximum mutual coupling occurred at the maturity stage of 60 % whereas the minimum occurred at 70%. These results demonstrate that this wireless sensor network can enable fruit growers to harvest their Durians at an appropriate time, provid-ing a reliable quality control for export.
Eggs of pests embedded in rice grains could be eradicated using a general domestic microwave oven... more Eggs of pests embedded in rice grains could be eradicated using a general domestic microwave oven operating at 2.45 GHz. Since the cooking chamber of a general microwave oven is small, it could not heat a lot of rice grains at once. It is therefore hard to make use of general domestic microwave oven in a small rice mill which produces a lot of rice grains every day. This paper presents a development of a microwave oven which is designed to use in a small rice mill to eradicate eggs of red flour beetles embedded in Thai Jasmine rice. Cooking chamber is designed to cope with rice grains having weight of 5 kilograms. From the experiment results, it is found that the designed microwave oven could effectively eradicate eggs of red flour beetles in 5 kg rice grains at 15 minutes heating time.
Since the point coordination function (PCF) in the IEEE 802.11 is based on a centralized polling ... more Since the point coordination function (PCF) in the IEEE 802.11 is based on a centralized polling protocol, some bandwidth is wasted due to the polling overheads and also due to null packets that are issued in case a polled station does not have any data to transmit. In order to reduce this waste and increase the channel utilization, we have proposed a modified version of the standard PCF. The modified PCF uses a distributed polling protocol (DPP) as the access mechanism for the uplink transmission of real-time traffic. The transmission period in the modified PCF consists of a distributed polling protocol period (DPPP) which is controlled by the DPP and the real-time traffic downlink period (RTDP). Our proposal further includes a technique for dealing with the hidden station problem for use together with the proposed modification. In this paper, an analytical analysis is done to compare the performance of the modified PCF with the standard PCF in terms of number of supportable statio...
A modified version of the point coordination func-tion (PCF) in the IEEE 802.11 standard called M... more A modified version of the point coordination func-tion (PCF) in the IEEE 802.11 standard called Mod-ified PCF has been introduced as an approach to im-prove channel utilization over the standard. It has been shown in our previous work that the utiliza-tion of the wireless channel can be significantly im-proved. In this paper, we investigate the performance of the Modified PCF when it is applied with a priority scheme to support prioritization for different traffic types such as interactive voice and video and real-time data. The investigation is done via simulation method. To illustrate the efficiency of the priority scheme, we compare its simulation results with some standardized protocols: the distributed coordination function (DCF), the enhanced distributed channel ac-cess (EDCA), and the standard PCF, and our previ-ously proposed protocol: the Modified PCF without priority scheme. The simulation results show that Modified PCF with priority scheme can provide bet-ter quality of s...
A modified version of the point coordination func- tion (PCF) in the IEEE 802.11 standard called ... more A modified version of the point coordination func- tion (PCF) in the IEEE 802.11 standard called Mod- ified PCF has been introduced as an approach to im- prove channel utilization over the standard. It has been shown in our previous work that the utiliza- tion of the wireless channel can be significantly im- proved. In this paper, we investigate the performance of the Modified PCF when it is applied with a priority scheme to support prioritization for dierent trac types such as interactive voice and video and real- time data. The investigation is done via simulation method. To illustrate the eciency of the priority scheme, we compare its simulation results with some standardized protocols: the distributed coordination function (DCF), the enhanced distributed channel ac- cess (EDCA), and the standard PCF, and our previ- ously proposed protocol: the Modified PCF without priority scheme. The simulation results show that Modified PCF with priority scheme can provide bet- ter quality of ...
In this letter, we present a wireless sensor network for monitoring the maturity stage of fruit. ... more In this letter, we present a wireless sensor network for monitoring the maturity stage of fruit. A dual-polari-zation coupled patch sensor, which is robust to environmental changes, was designed to operate at 2.45 GHz. It was attached to a Durian fruit for a period of days to measure the magnitude of mutual coupling corre-sponding mainly to the starch concentration of its pulp. Signal was transmitted from a sensor node, via tree nodes, to a master node that displays the variations occurring in the period. The maximum mutual coupling occurred at the maturity stage of 60 % whereas the minimum occurred at 70%. These results demonstrate that this wireless sensor network can enable fruit growers to harvest their Durians at an appropriate time, provid-ing a reliable quality control for export.
Eggs of pests embedded in rice grains could be eradicated using a general domestic microwave oven... more Eggs of pests embedded in rice grains could be eradicated using a general domestic microwave oven operating at 2.45 GHz. Since the cooking chamber of a general microwave oven is small, it could not heat a lot of rice grains at once. It is therefore hard to make use of general domestic microwave oven in a small rice mill which produces a lot of rice grains every day. This paper presents a development of a microwave oven which is designed to use in a small rice mill to eradicate eggs of red flour beetles embedded in Thai Jasmine rice. Cooking chamber is designed to cope with rice grains having weight of 5 kilograms. From the experiment results, it is found that the designed microwave oven could effectively eradicate eggs of red flour beetles in 5 kg rice grains at 15 minutes heating time.
Since the point coordination function (PCF) in the IEEE 802.11 is based on a centralized polling ... more Since the point coordination function (PCF) in the IEEE 802.11 is based on a centralized polling protocol, some bandwidth is wasted due to the polling overheads and also due to null packets that are issued in case a polled station does not have any data to transmit. In order to reduce this waste and increase the channel utilization, we have proposed a modified version of the standard PCF. The modified PCF uses a distributed polling protocol (DPP) as the access mechanism for the uplink transmission of real-time traffic. The transmission period in the modified PCF consists of a distributed polling protocol period (DPPP) which is controlled by the DPP and the real-time traffic downlink period (RTDP). Our proposal further includes a technique for dealing with the hidden station problem for use together with the proposed modification. In this paper, an analytical analysis is done to compare the performance of the modified PCF with the standard PCF in terms of number of supportable statio...
A modified version of the point coordination func-tion (PCF) in the IEEE 802.11 standard called M... more A modified version of the point coordination func-tion (PCF) in the IEEE 802.11 standard called Mod-ified PCF has been introduced as an approach to im-prove channel utilization over the standard. It has been shown in our previous work that the utiliza-tion of the wireless channel can be significantly im-proved. In this paper, we investigate the performance of the Modified PCF when it is applied with a priority scheme to support prioritization for different traffic types such as interactive voice and video and real-time data. The investigation is done via simulation method. To illustrate the efficiency of the priority scheme, we compare its simulation results with some standardized protocols: the distributed coordination function (DCF), the enhanced distributed channel ac-cess (EDCA), and the standard PCF, and our previ-ously proposed protocol: the Modified PCF without priority scheme. The simulation results show that Modified PCF with priority scheme can provide bet-ter quality of s...
A modified version of the point coordination func- tion (PCF) in the IEEE 802.11 standard called ... more A modified version of the point coordination func- tion (PCF) in the IEEE 802.11 standard called Mod- ified PCF has been introduced as an approach to im- prove channel utilization over the standard. It has been shown in our previous work that the utiliza- tion of the wireless channel can be significantly im- proved. In this paper, we investigate the performance of the Modified PCF when it is applied with a priority scheme to support prioritization for dierent trac types such as interactive voice and video and real- time data. The investigation is done via simulation method. To illustrate the eciency of the priority scheme, we compare its simulation results with some standardized protocols: the distributed coordination function (DCF), the enhanced distributed channel ac- cess (EDCA), and the standard PCF, and our previ- ously proposed protocol: the Modified PCF without priority scheme. The simulation results show that Modified PCF with priority scheme can provide bet- ter quality of ...
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Papers by Apichan Kanjanavapastit