Relative positioning is one of the important techniques in collaborativerobotics, autonomous vehicles, and virtual/augmented reality (VR/AR)applications. Recently, ultra-wideband (UWB) has been utilized to calculatere...Relative positioning is one of the important techniques in collaborativerobotics, autonomous vehicles, and virtual/augmented reality (VR/AR)applications. Recently, ultra-wideband (UWB) has been utilized to calculaterelative position as it does not require a line of sight compared to a camerato calculate the range between two objects with centimeter-level accuracy.However, the single UWB range measurement cannot provide the relativeposition and attitude of any device in three dimensions (3D) because oflacking bearing information. In this paper, we have proposed a UWB-IMUfusion-based relative position system to provide accurate relative positionand attitude between wearable Internet of Things (IoT) devices in 3D. Weintroduce a distributed Euler angle antenna orientationwhich can be equippedwith the mobile structure to enable relative positioning. Moving average andmin-max removing preprocessing filters are introduced to reduce the standarddeviation. The standard multilateration method is modified to calculate therelative position between mobile structures. We combine UWB and IMUmeasurements in a probabilistic framework that enables users to calculatethe relative position between two nodes with less error. We have carried outdifferent experiments to illustrate the advantages of fusing IMU and UWBranges for relative positioning systems. We have achieved a mean accuracy of0.31m for 3D relative positioning in indoor line of sight conditions.展开更多
Long Range Wide Area Network (LoRaWAN) in the Internet ofThings (IoT) domain has been the subject of interest for researchers. Thereis an increasing demand to localize these IoT devices using LoRaWAN dueto the quickly...Long Range Wide Area Network (LoRaWAN) in the Internet ofThings (IoT) domain has been the subject of interest for researchers. Thereis an increasing demand to localize these IoT devices using LoRaWAN dueto the quickly growing number of IoT devices. LoRaWAN is well suited tosupport localization applications in IoTs due to its low power consumptionand long range. Multiple approaches have been proposed to solve the localizationproblem using LoRaWAN. The Expected Signal Power (ESP) basedtrilateration algorithm has the significant potential for localization becauseESP can identify the signal’s energy below the noise floor with no additionalhardware requirements and ease of implementation. This research articleoffers the technical evaluation of the trilateration technique, its efficiency,and its limitations for the localization using LoRa ESP in a large outdoorpopulated campus environment. Additionally, experimental evaluations areconducted to determine the effects of frequency hopping, outlier removal, andincreasing the number of gateways on localization accuracy. Results obtainedfrom the experiment show the importance of calculating the path loss exponentfor every frequency to circumvent the high localization error because ofthe frequency hopping, thus improving the localization performance withoutthe need of using only a single frequency.展开更多
Localization of sensor nodes is crucial in Wireless Sensor Network because of applications like surveillance, tracking, navigation etc. Various optimization techniques for localization have been proposed in literature...Localization of sensor nodes is crucial in Wireless Sensor Network because of applications like surveillance, tracking, navigation etc. Various optimization techniques for localization have been proposed in literature by different researchers. In this paper, we propose a two phase hybrid approach for localization using Multidi- mensional Scaling and trilateration, namely, MDS with refinement using trilateration. Trilateration refines the estimated locations obtained by the MDS algorithm and hence acts as a post optimizer which improves the accuracy of the estimated positions of sensor nodes. Through extensive simulations, we have shown that the proposed algorithm is more robust to noise than previous approaches and provides higher accuracy for estimating the positions of sensor nodes.展开更多
Five-hundred-meter Aperture Spherical radio Telescope( FAST) is the largest sensitive single dish radio telescope in the world,in which the control and measurement of the feed is one crucial section of the FAST contro...Five-hundred-meter Aperture Spherical radio Telescope( FAST) is the largest sensitive single dish radio telescope in the world,in which the control and measurement of the feed is one crucial section of the FAST control system. Trilateration is presented to obtain three-dimensional coordinate for tracking feed focus cabin. Every three total stations chase prism movement to be attached on feed focus cabin and the prism position is determined from the measured distances based on the principle of trilateration. Therefore,feed position is determined from three prisms on the focus cabin. This study is to assess the accuracy and reliability of trilateration calculation on tracking focus cabin of FAST. Different arrangement of total stations on trilateration is theoretically studied. Through experiment,the proposed method shows that the accuracy is better than that of the polar coordinate measurement. The average root mean square error is lower than 0. 6 mm,which is found to have high accuracy and reliability.展开更多
Numerous innovative heat recovery-to-power technologies have been resourcefully and technologically exploited to bridge the growing gap between energy needs and its sustainable and affordable supply.Among them,the pro...Numerous innovative heat recovery-to-power technologies have been resourcefully and technologically exploited to bridge the growing gap between energy needs and its sustainable and affordable supply.Among them,the proposed trilateral-cycle(TLC) power system exhibits high thermodynamic efficiency during heat recovery-to-power from low-to-medium temperature heat sources.The TLCs are proposed and analysed using n-pentane as working fluid for waste heat recovery-to-power generation from low-grade heat source to evaluate the thermodynamic efficiency of the cycles.Four different single stage TLC configurations with distinct working principles are modelled thermodynamically using engineering equation solver.Based on the thermodynamic framework,thermodynamic performance simulation and efficiency analysis of the cycles as well as the exergy efficiencies of the heating and condensing processes are carried out and compared in their efficiency.The results show that the simple TLC,recuperated TLC,reheat TLC and regenerative TLC operating at subcritical conditions with cycle high temperature of 473 K can attain thermal efficiencies of 21.97%,23.91%,22.07% and 22.9%,respectively.The recuperated TLC attains the highest thermodynamic efficiency at the cycle high temperature because of its lowest exergy destruction rates in the heat exchanger and condenser.The efficiency analysis carried out would assist in guiding thermodynamic process development and thermal integration of the proposed cycles.展开更多
Germany has gradually increased its investment in Africa.In addition to promoting traditional economic and trade cooperation,Germany has paid more attention to security issues in Africa and to improved cooperation in ...Germany has gradually increased its investment in Africa.In addition to promoting traditional economic and trade cooperation,Germany has paid more attention to security issues in Africa and to improved cooperation in defense,immigration and counter-terrorism.As Germany explores new models of development aid and encourages renewable energy and environmental protection in African countries,German capability and willingness to cooperate with African nations are on the rise.While Germany welcomes the African consumer market,historic problems centering on value differences and the European Union’s diplomatic constraints obstruct German-African cooperation over the short term.Germany promotes trilateral cooperation with China and Africa but encounters several challenges within its forward momentum.展开更多
<div style="text-align:justify;"> Aiming at the problems of LED-based visible light positioning system such as unstable illumination, Lambertian model transmission limitation, large positioning error, ...<div style="text-align:justify;"> Aiming at the problems of LED-based visible light positioning system such as unstable illumination, Lambertian model transmission limitation, large positioning error, etc., it is proposed to use PWM to drive the LED, use the curve fitting method to obtain the ranging model, and estimate the target position according to the trilateral algorithm. A positioning system platform based on the microcontroller MiniSTM32 was built to test the performance of the transceiver circuit. The experimental results showed that the positioning error of less than 3 cm was achieved in a space of 80 cm × 80 cm × 80 cm. </div>展开更多
This paper aims to present a digital radio broadcasting system that explores the advantages of pseudo-random codes. In this context, a transmitter and its dual receiver are able to reuse frequency spectrum bands witho...This paper aims to present a digital radio broadcasting system that explores the advantages of pseudo-random codes. In this context, a transmitter and its dual receiver are able to reuse frequency spectrum bands without interfering on other existing communication systems. It is proposed a communication system that allows radio broadcasting with the following characteristics: lower transmission power, new communication channels and digital signal processing techinques to add positioning services in two dimensions.展开更多
The current phase of China-Africa relations in the UN system are underlined by the alignment of the three broad plans： the AU＇ Agenda 2063t the FOCAC action plans for the period 2015-18 and the UN Sustainable Develo...The current phase of China-Africa relations in the UN system are underlined by the alignment of the three broad plans： the AU＇ Agenda 2063t the FOCAC action plans for the period 2015-18 and the UN Sustainable Development Goals.展开更多
The geopolitical construct of the Indo-Pacific has evolved as one of the most important ones of the twenty-first century and more particularly of the last decade.While there is little or no consensus on where the Indo...The geopolitical construct of the Indo-Pacific has evolved as one of the most important ones of the twenty-first century and more particularly of the last decade.While there is little or no consensus on where the Indo-Pacific Region(IPR)begins or ends,it has inadvertently become a space where new convergences,competitions and alignments have emerged.These developments are intrinsically linked with the ascent of China as a global power,the retreat of the American strategic footprint and the emergence of a multi-polar world order.Within the larger Indo-Pacific construct,the Western Indian Ocean region is a space of considerable geopolitical and maritime interactions between states.The United Arab Emirates(UAE)and India are both countries of the Western Indian Ocean region while France is a resident power of the region owing to the presence of two of its overseas departments-Mayotte and Reunion—and its inter services bases in the UAE and Djibouti.The three countries have considerable experience in operationalising bilateral as well as trilateral initiatives.The lack of such initiatives in the Western Indian Ocean region could therefore offer the opportunity for UAE,India and France to come together in a trilateral arrangement to further their strategic interests and uphold the concept of a‘free and open Indo-Pacific’.The paper seeks to explore whether a trilateral partnership between the UAE,India and France could contribute to furthering their respective strategic autonomy in the Indo-Pacific Region.The paper will also endeavour to examine the conflicts and differences that could be expected and the possible areas of convergence.展开更多
基金supported by Samsung Advanced Institute of Technology and partly supported by the National Research Foundation of Korea (NRF)grant funded by the Korean government (MSIT) (2022R1F1A1063662).
文摘Relative positioning is one of the important techniques in collaborativerobotics, autonomous vehicles, and virtual/augmented reality (VR/AR)applications. Recently, ultra-wideband (UWB) has been utilized to calculaterelative position as it does not require a line of sight compared to a camerato calculate the range between two objects with centimeter-level accuracy.However, the single UWB range measurement cannot provide the relativeposition and attitude of any device in three dimensions (3D) because oflacking bearing information. In this paper, we have proposed a UWB-IMUfusion-based relative position system to provide accurate relative positionand attitude between wearable Internet of Things (IoT) devices in 3D. Weintroduce a distributed Euler angle antenna orientationwhich can be equippedwith the mobile structure to enable relative positioning. Moving average andmin-max removing preprocessing filters are introduced to reduce the standarddeviation. The standard multilateration method is modified to calculate therelative position between mobile structures. We combine UWB and IMUmeasurements in a probabilistic framework that enables users to calculatethe relative position between two nodes with less error. We have carried outdifferent experiments to illustrate the advantages of fusing IMU and UWBranges for relative positioning systems. We have achieved a mean accuracy of0.31m for 3D relative positioning in indoor line of sight conditions.
基金the ADEK Award for Research Excellence (AARE19-245)2019.
文摘Long Range Wide Area Network (LoRaWAN) in the Internet ofThings (IoT) domain has been the subject of interest for researchers. Thereis an increasing demand to localize these IoT devices using LoRaWAN dueto the quickly growing number of IoT devices. LoRaWAN is well suited tosupport localization applications in IoTs due to its low power consumptionand long range. Multiple approaches have been proposed to solve the localizationproblem using LoRaWAN. The Expected Signal Power (ESP) basedtrilateration algorithm has the significant potential for localization becauseESP can identify the signal’s energy below the noise floor with no additionalhardware requirements and ease of implementation. This research articleoffers the technical evaluation of the trilateration technique, its efficiency,and its limitations for the localization using LoRa ESP in a large outdoorpopulated campus environment. Additionally, experimental evaluations areconducted to determine the effects of frequency hopping, outlier removal, andincreasing the number of gateways on localization accuracy. Results obtainedfrom the experiment show the importance of calculating the path loss exponentfor every frequency to circumvent the high localization error because ofthe frequency hopping, thus improving the localization performance withoutthe need of using only a single frequency.
文摘Localization of sensor nodes is crucial in Wireless Sensor Network because of applications like surveillance, tracking, navigation etc. Various optimization techniques for localization have been proposed in literature by different researchers. In this paper, we propose a two phase hybrid approach for localization using Multidi- mensional Scaling and trilateration, namely, MDS with refinement using trilateration. Trilateration refines the estimated locations obtained by the MDS algorithm and hence acts as a post optimizer which improves the accuracy of the estimated positions of sensor nodes. Through extensive simulations, we have shown that the proposed algorithm is more robust to noise than previous approaches and provides higher accuracy for estimating the positions of sensor nodes.
基金Supported by the National Natural Science Foundation of China(No.11273001,11373001,11703046)
文摘Five-hundred-meter Aperture Spherical radio Telescope( FAST) is the largest sensitive single dish radio telescope in the world,in which the control and measurement of the feed is one crucial section of the FAST control system. Trilateration is presented to obtain three-dimensional coordinate for tracking feed focus cabin. Every three total stations chase prism movement to be attached on feed focus cabin and the prism position is determined from the measured distances based on the principle of trilateration. Therefore,feed position is determined from three prisms on the focus cabin. This study is to assess the accuracy and reliability of trilateration calculation on tracking focus cabin of FAST. Different arrangement of total stations on trilateration is theoretically studied. Through experiment,the proposed method shows that the accuracy is better than that of the polar coordinate measurement. The average root mean square error is lower than 0. 6 mm,which is found to have high accuracy and reliability.
基金The University of Ilorin,Nigeria financially supported this research through scholarship grant from Tertiary Education Trust Fund
文摘Numerous innovative heat recovery-to-power technologies have been resourcefully and technologically exploited to bridge the growing gap between energy needs and its sustainable and affordable supply.Among them,the proposed trilateral-cycle(TLC) power system exhibits high thermodynamic efficiency during heat recovery-to-power from low-to-medium temperature heat sources.The TLCs are proposed and analysed using n-pentane as working fluid for waste heat recovery-to-power generation from low-grade heat source to evaluate the thermodynamic efficiency of the cycles.Four different single stage TLC configurations with distinct working principles are modelled thermodynamically using engineering equation solver.Based on the thermodynamic framework,thermodynamic performance simulation and efficiency analysis of the cycles as well as the exergy efficiencies of the heating and condensing processes are carried out and compared in their efficiency.The results show that the simple TLC,recuperated TLC,reheat TLC and regenerative TLC operating at subcritical conditions with cycle high temperature of 473 K can attain thermal efficiencies of 21.97%,23.91%,22.07% and 22.9%,respectively.The recuperated TLC attains the highest thermodynamic efficiency at the cycle high temperature because of its lowest exergy destruction rates in the heat exchanger and condenser.The efficiency analysis carried out would assist in guiding thermodynamic process development and thermal integration of the proposed cycles.
文摘Germany has gradually increased its investment in Africa.In addition to promoting traditional economic and trade cooperation,Germany has paid more attention to security issues in Africa and to improved cooperation in defense,immigration and counter-terrorism.As Germany explores new models of development aid and encourages renewable energy and environmental protection in African countries,German capability and willingness to cooperate with African nations are on the rise.While Germany welcomes the African consumer market,historic problems centering on value differences and the European Union’s diplomatic constraints obstruct German-African cooperation over the short term.Germany promotes trilateral cooperation with China and Africa but encounters several challenges within its forward momentum.
文摘<div style="text-align:justify;"> Aiming at the problems of LED-based visible light positioning system such as unstable illumination, Lambertian model transmission limitation, large positioning error, etc., it is proposed to use PWM to drive the LED, use the curve fitting method to obtain the ranging model, and estimate the target position according to the trilateral algorithm. A positioning system platform based on the microcontroller MiniSTM32 was built to test the performance of the transceiver circuit. The experimental results showed that the positioning error of less than 3 cm was achieved in a space of 80 cm × 80 cm × 80 cm. </div>
文摘This paper aims to present a digital radio broadcasting system that explores the advantages of pseudo-random codes. In this context, a transmitter and its dual receiver are able to reuse frequency spectrum bands without interfering on other existing communication systems. It is proposed a communication system that allows radio broadcasting with the following characteristics: lower transmission power, new communication channels and digital signal processing techinques to add positioning services in two dimensions.
文摘The current phase of China-Africa relations in the UN system are underlined by the alignment of the three broad plans： the AU＇ Agenda 2063t the FOCAC action plans for the period 2015-18 and the UN Sustainable Development Goals.
文摘The geopolitical construct of the Indo-Pacific has evolved as one of the most important ones of the twenty-first century and more particularly of the last decade.While there is little or no consensus on where the Indo-Pacific Region(IPR)begins or ends,it has inadvertently become a space where new convergences,competitions and alignments have emerged.These developments are intrinsically linked with the ascent of China as a global power,the retreat of the American strategic footprint and the emergence of a multi-polar world order.Within the larger Indo-Pacific construct,the Western Indian Ocean region is a space of considerable geopolitical and maritime interactions between states.The United Arab Emirates(UAE)and India are both countries of the Western Indian Ocean region while France is a resident power of the region owing to the presence of two of its overseas departments-Mayotte and Reunion—and its inter services bases in the UAE and Djibouti.The three countries have considerable experience in operationalising bilateral as well as trilateral initiatives.The lack of such initiatives in the Western Indian Ocean region could therefore offer the opportunity for UAE,India and France to come together in a trilateral arrangement to further their strategic interests and uphold the concept of a‘free and open Indo-Pacific’.The paper seeks to explore whether a trilateral partnership between the UAE,India and France could contribute to furthering their respective strategic autonomy in the Indo-Pacific Region.The paper will also endeavour to examine the conflicts and differences that could be expected and the possible areas of convergence.
