Proceedings of the International Conference on Modeling Analysis and Simulation of Wireless and Mobile Systems on International Conference on Modeling Analysis and Simulation of Wireless and Mobile Systems
We introduce, design, and evaluate a set of universal receiver beamforming techniques. Our approa... more We introduce, design, and evaluate a set of universal receiver beamforming techniques. Our approach and system DEFORM, a Deep Learning (DL)-based RX beamforming achieves significant gain for multi-antenna RF receivers while being agnostic to the transmitted signal features (e.g., modulation or bandwidth). It is well known that combining coherent RF signals from multiple antennas results in a beamforming gain proportional to the number of receiving elements. However in practice, this approach heavily relies on explicit channel estimation techniques, which are link specific and require significant communication overhead to be transmitted to the receiver. DEFORM addresses this challenge by leveraging Convolutional Neural Network to estimate the channel characteristics in particular the relative phase to antenna elements. It is specifically designed to address the unique features of wireless signals complex samples, such as the ambiguous 2 phase discontinuity and the high sensitivity of the link Bit Error Rate. The channel prediction is subsequently used in the Maximum Ratio Combining algorithm to achieve an optimal combination of the received signals. While being trained on a fixed, basic RF settings, we show that DEFORM's DL model is universal, achieving up to 3 dB of SNR gain for a twoantenna receiver in extensive evaluation demonstrating various settings of modulations and bandwidths. CCS CONCEPTS • Networks → Wireless access networks; • Computing methodologies → Neural networks.
We introduce, design, and evaluate a set of universal receiver beamforming techniques. Our approa... more We introduce, design, and evaluate a set of universal receiver beamforming techniques. Our approach and system DEFORM, a Deep Learning (DL)-based RX beamforming achieves significant gain for multi-antenna RF receivers while being agnostic to the transmitted signal features (e.g., modulation or bandwidth). It is well known that combining coherent RF signals from multiple antennas results in a beamforming gain proportional to the number of receiving elements. However in practice, this approach heavily relies on explicit channel estimation techniques, which are link specific and require significant communication overhead to be transmitted to the receiver. DEFORM addresses this challenge by leveraging Convolutional Neural Network to estimate the channel characteristics in particular the relative phase to antenna elements. It is specifically designed to address the unique features of wireless signals complex samples, such as the ambiguous 2 phase discontinuity and the high sensitivity of the link Bit Error Rate. The channel prediction is subsequently used in the Maximum Ratio Combining algorithm to achieve an optimal combination of the received signals. While being trained on a fixed, basic RF settings, we show that DEFORM's DL model is universal, achieving up to 3 dB of SNR gain for a twoantenna receiver in extensive experiments demonstrating various settings of modulations, bandwidths, and channels. The universality of DEFORM is demonstrated through joint beamforming-relaying of LoRa (Chirp Spread Spectrum modulation) and ZigBee signals, achieving significant improvements to Packet Loss/Delivery Rates relatively to conventional Amplify-and-Forward (LoRa PLR reduced by 23 times and ZigBee PDR increased by 8 times).
Accessing and interacting with difficult to reach surfaces at various orientations is of interest... more Accessing and interacting with difficult to reach surfaces at various orientations is of interest within a variety of industrial contexts. Thus far, the predominant robotic solution to such a problem has been to leverage the maneuverability of a fully actuated, omnidirectional aerial manipulator. Such an approach, however, requires a specialised system with a high relative degree of complexity, thus reducing platform endurance and real-world applicability. The work here presents a new aerial system composed of a parallel manipulator and conventional, underactuated multirotor flying base to demonstrate interaction with vertical and non-vertical surfaces. Our solution enables compliance to external disturbance on both subsystems, the manipulator and flying base, independently with a goal of improved overall system performance when interacting with surfaces. To achieve this behaviour, an admittance control strategy is implemented on various layers of the flying base's dynamics together with torque limits imposed on the manipulator actuators. Experimental evaluations show that the proposed system is compliant to external perturbations while allowing for differing interaction behaviours as compliance parameters of each subsystem are altered. Such capabilities enable an adjustable form of dexterity in completing sensor installation, inspection and aerial physical interaction tasks. A video of our system interacting with various surfaces can be found here: https://youtu.be/38neGb8-lXg.
Bone's homeostasis is only achieved when there is a balance between bone formation and bone r... more Bone's homeostasis is only achieved when there is a balance between bone formation and bone resorption. A metabolic disorder of bone-resorbing osteoclasts can lead to osteoporosis. Long-term use of anti-osteoporosis drugs can lead to undesirable side effects so traditional herbal can be a potential source of alternative medicine. In the present study, forty one Vietnamese plants (seventy methanol extracts) were screened for osteoclastogenesis inhibitory activities on RAW264.7 mouse macrophage cells. For the first time, 29 extracts from 24 species showed potential as effective inhibitors of osteoclastogenesis.
Allocating scarce resources with (weak) priority and complex constraints has many applications ra... more Allocating scarce resources with (weak) priority and complex constraints has many applications ranging from course allocation, and healthcare rationing to refugee resettlement. Its generality, however, mostly leads to impossibility results. We offer a positive result with a mechanism based on a new concept called competitive stable equilibrium. This is a natural extension of competitive equilibrium with endowed budgets that accommodates weak priorities. Specifically, an agent only needs to pay for a resource if it belongs to the last tier among the agents currently consuming the resource. This concept applies to both frameworks of one-sided and two-sided markets in a unifying way and allows for a more flexible tie-breaking rule by giving agents different budgets. We empirically apply our mechanism to reassign season tickets to families in the presence of social distancing. Our simulation results show that our method outperforms existing ones in both efficiency and fairness measures.
Proceedings of the AAAI Conference on Artificial Intelligence
We describe a tool, MatchMaps, that generates sameAs and partOf matches between spatial objects (... more We describe a tool, MatchMaps, that generates sameAs and partOf matches between spatial objects (such as shops, shopping centres, etc.) in crowd-sourced and authoritative geospatial datasets. MatchMaps uses reasoning in qualitative spatial logic, description logic and truth maintenance techniques, to produce a consistent set of matches. We report the results of an initial evaluation of MatchMaps by experts from Ordnance Survey (Great Britain’s National Mapping Authority). In both the case studies considered, MatchMaps was able to correctly match spatial objects (high precision and recall) with minimal human intervention.
Proceedings of the AAAI Conference on Artificial Intelligence
In many logic-based BDI agent programming languages, plan selection involves inferencing over som... more In many logic-based BDI agent programming languages, plan selection involves inferencing over some underlying knowledge representation. While context-sensitive plan selection facilitates the development of flexible, declarative programs, the overhead of evaluating repeated queries to the agent's beliefs and goals can result in poor run time performance. In this paper we present an approach to multi-cycle query caching for logic-based BDI agent programming languages. We extend the abstract performance model presented in (Alechina et al. 2012) to quantify the costs and benefits of caching query results over multiple deliberation cycles. We also present results of experiments with prototype implementations of both single- and multi-cycle caching in three logic-based BDI agent platforms, which demonstrate that significant performance improvements are achievable in practice.
Four neolignans, (7S,8S)-dihydrodehydrodiconiferyl alcohol 9-O-β-D-glucopyranoside (1), (7S,8S)-d... more Four neolignans, (7S,8S)-dihydrodehydrodiconiferyl alcohol 9-O-β-D-glucopyranoside (1), (7S,8S)-dihydrodehydrodiconiferyl alcohol 9′-O-β-D-glucopyranoside (2), (7S,8R)-5-methoxydihydrodehydrodiconiferyl alcohol 4-O-β-D-glucopyranoside (3), and (7S,8R)-5-methoxydihydrodehydrodiconiferyl alcohol 9′-O-β-D-glucopyranoside (4) and five flavonol glycosides, kaempferol-3-O-β-D-glucopyranoside (5), kaempferol 3-O-rutinoside (6), kaempferol 3-O-α-L-rhamnopyranosyl (1→6)-β-D-galactopyranoside (7), kaempferol 3-O-β-D-galactopyranoside (8), and quercetin 3-O-β-D-glucopyranoside (9) were isolated from the methanol extract of Viburnum lutescens Blume leaves. Their chemical structures were elucidated by 1D- and 2D-NMR spectra and comparison with those reported in the literature. Compounds 1, 2, and 4 were reported from Viburnum genus for the first time.
Wireless links are increasingly used to deliver critical services, while intentional interference... more Wireless links are increasingly used to deliver critical services, while intentional interference (jamming) remains a very serious threat to such services. In this paper, we are concerned with the design and evaluation of a universal anti-jamming building block, that is agnostic to the specifics of the communication link and can therefore be combined with existing technologies. We believe that such a block should not require explicit probes, sounding, training sequences, channel estimation, or even the cooperation of the transmitter. To meet these requirements, we propose an approach that relies on advances in Machine Learning, and the promises of neural accelerators and software defined radios. We identify and address multiple challenges, resulting in a convolutional neural network architecture and models for a multi-antenna system to infer the existence of interference, the number of interfering emissions and their respective phases. This information is continuously fed into an algorithm that cancels the interfering signal. We develop a twoantenna prototype system and evaluate our jamming cancellation approach in various environment settings and modulation schemes using Software Defined Radio platforms. We demonstrate that the receiving node equipped with our approach can detect a jammer with over 99% of accuracy and achieve a Bit Error Rate (BER) as low as 10 −6 even when the jammer power is nearly two orders of magnitude (18 dB) higher than the legitimate signal, and without requiring modifications to the link modulation. In non-adversarial settings, our approach can have other advantages such as detecting and mitigating collisions.
Innovative side-channel attacks have repeatedly exposed the secrets of cryptosystems. Benhamouda,... more Innovative side-channel attacks have repeatedly exposed the secrets of cryptosystems. Benhamouda, Degwekar, Ishai, and Rabin (CRYPTO–2018) introduced local leakage resilience of secret-sharing schemes to study some of these vulnerabilities. In this framework, the objective is to characterize the unintended information revelation about the secret by obtaining independent leakage from each secret share. This work accurately quantifies the vulnerability of the additive secret-sharing scheme to local leakage attacks and its consequences to other secret-sharing schemes. Consider the additive secret-sharing scheme over a prime field among k parties, where the secret shares are stored in their natural binary representation, requiring λ bits – the security parameter. We prove that the reconstruction threshold k = ω(log λ) is necessary to protect against local physical-bit probing attacks, improving the previous ω(log λ/ log log λ) lower bound. This result is a consequence of accurately dete...
As in many developing countries, landfill is considered to be the most suitable waste disposal me... more As in many developing countries, landfill is considered to be the most suitable waste disposal method in Vietnam. However, landfill and its related issues have caused a number of serious environmental conflicts. To manage the municipal waste disposed to landfill properly and effectively in order to minimize the associated pollutions and prolong the duration of landfill, it requires a comprehensive and challenging solution to those conflicts. Reducing the household waste, therefore, should be considered as prerequisite in solving these conflicts. Household waste unit pricing is proved in many countries to be an effective measure in reducing the household waste and improving people´s awareness of household waste management. In this thesis, an empirical research through a survey in the communities of all 6 urban districts of Da Nang city in Vietnam, where Khanh Son landfill located, is conducted. The survey focuses on general awareness of household waste of the people in these communit...
Secure multi-party computation (MPC) allows mutually distrusting parties to compute securely over... more Secure multi-party computation (MPC) allows mutually distrusting parties to compute securely over their private data. The hardness of MPC, essentially, lies in performing secure multiplications over suitable algebras. There are several cryptographic resources that help securely compute one multiplication over a large finite field, say GF [2 n ], with linear communication complexity. For example, the computational hardness assumption like noisy Reed-Solomon codewords are pseudorandom. However, it is not known if we can securely compute, say, a linear number of AND-gates from such resources, i.e., a linear number of multiplications over the base field GF [2]. Before our work, we could only perform o(n) secure AND-evaluations. Technically, we construct a perfectly secure protocol that realizes a linear number of multiplication gates over the base field using one multiplication gate over a degree-n extension field. This construction relies on the toolkit provided by algebraic function fields. Using this construction, we obtain the following results. We provide the first construction that computes a linear number of oblivious transfers with linear communication complexity from the computational hardness assumptions like noisy Reed-Solomon codewords are pseudorandom, or arithmetic-analogues of LPN-style assumptions. Next, we highlight the potential of our result for other applications to MPC by constructing the first correlation extractor that has 1/2 resilience and produces a linear number of oblivious transfers.
Proceedings of the 2019 ACM Conference on Economics and Computation, 2019
We consider a new model of many-to-one matching markets in which agents with multi-unit demand ai... more We consider a new model of many-to-one matching markets in which agents with multi-unit demand aim to maximize a cardinal linear objective subject to multidimensional knapsack constraints. The choice functions of agents with multi-unit demand are therefore not substitutable. As a result, pairwise stable matchings may not exist and, even when they do, may be highly inefficient. We provide an algorithm that finds a groupstable matching that approximately satisfies all the multidimensional knapsack constraints. The degree of the constraint violation is proportional to the sparsity of the constraint matrix. The algorithm therefore provides practical error bounds for applications in several contexts, such as refugee resettlement, matching of children to daycare centers, and meeting diversity requirements in colleges. A novel ingredient in our algorithm is a combination of matching with contracts and Scarf's Lemma. For full version of our paper, please see http://web.ics.purdue.edu/ nguye161/complexconstraint.pdf. CCS Concepts: • Social and professional topics; • Theory of computation → Algorithmic game theory and mechanism design;
An increasing number of organisations are turning to knowledge management (KM) as a key to levera... more An increasing number of organisations are turning to knowledge management (KM) as a key to leverage their distinctive core competencies in their pursuit of competitive advantage. Organisations are interested in KM to boost the efficiency of their processes, increase their productivity and quality of their services, and to achieve innovative solutions and products for their customers. Consequently, the contributions of KM to the overall success of an organisation have been widely acknowledged. Prior research studies have demonstrated that both organisational culture and leadership behaviours are widely held to be major barriers to creating and leveraging knowledge. The literature suggests that for KM implementation to be effective there is a need to diagnose the fit between an organisation and its KM objectives. Thus, it is essential to articulate how organisational culture and leadership styles affect the organisation’s ability to create and apply knowledge. It is only then that app...
In this paper, we introduce a new robust procedure to identify material parameters of mechanical ... more In this paper, we introduce a new robust procedure to identify material parameters of mechanical models from full-field measurements. It is based on data information coming from the Digital Image Correlation technique. The procedure aims at defining a suitable numerical processing, in terms of model selection and discretization mesh, with respect to information and noise contained in the data. The nature of the procedure is to minimize a cost functional based on the modified Constitutive Relation Error concept, which is made of modeling and measurement terms. Constructing an admissible stress field, verifying the equilibration equation in a full sense, enables one to obtain estimates on both discretization and modeling errors, which can then be compared with measurement noise in order to drive mesh adaptation and model enrichment. In addition, the procedure is coupled with reduced order modeling techniques in order to optimize computation costs. The overall approach is implemented o...
Proceedings of the International Conference on Modeling Analysis and Simulation of Wireless and Mobile Systems on International Conference on Modeling Analysis and Simulation of Wireless and Mobile Systems
We introduce, design, and evaluate a set of universal receiver beamforming techniques. Our approa... more We introduce, design, and evaluate a set of universal receiver beamforming techniques. Our approach and system DEFORM, a Deep Learning (DL)-based RX beamforming achieves significant gain for multi-antenna RF receivers while being agnostic to the transmitted signal features (e.g., modulation or bandwidth). It is well known that combining coherent RF signals from multiple antennas results in a beamforming gain proportional to the number of receiving elements. However in practice, this approach heavily relies on explicit channel estimation techniques, which are link specific and require significant communication overhead to be transmitted to the receiver. DEFORM addresses this challenge by leveraging Convolutional Neural Network to estimate the channel characteristics in particular the relative phase to antenna elements. It is specifically designed to address the unique features of wireless signals complex samples, such as the ambiguous 2 phase discontinuity and the high sensitivity of the link Bit Error Rate. The channel prediction is subsequently used in the Maximum Ratio Combining algorithm to achieve an optimal combination of the received signals. While being trained on a fixed, basic RF settings, we show that DEFORM's DL model is universal, achieving up to 3 dB of SNR gain for a twoantenna receiver in extensive evaluation demonstrating various settings of modulations and bandwidths. CCS CONCEPTS • Networks → Wireless access networks; • Computing methodologies → Neural networks.
We introduce, design, and evaluate a set of universal receiver beamforming techniques. Our approa... more We introduce, design, and evaluate a set of universal receiver beamforming techniques. Our approach and system DEFORM, a Deep Learning (DL)-based RX beamforming achieves significant gain for multi-antenna RF receivers while being agnostic to the transmitted signal features (e.g., modulation or bandwidth). It is well known that combining coherent RF signals from multiple antennas results in a beamforming gain proportional to the number of receiving elements. However in practice, this approach heavily relies on explicit channel estimation techniques, which are link specific and require significant communication overhead to be transmitted to the receiver. DEFORM addresses this challenge by leveraging Convolutional Neural Network to estimate the channel characteristics in particular the relative phase to antenna elements. It is specifically designed to address the unique features of wireless signals complex samples, such as the ambiguous 2 phase discontinuity and the high sensitivity of the link Bit Error Rate. The channel prediction is subsequently used in the Maximum Ratio Combining algorithm to achieve an optimal combination of the received signals. While being trained on a fixed, basic RF settings, we show that DEFORM's DL model is universal, achieving up to 3 dB of SNR gain for a twoantenna receiver in extensive experiments demonstrating various settings of modulations, bandwidths, and channels. The universality of DEFORM is demonstrated through joint beamforming-relaying of LoRa (Chirp Spread Spectrum modulation) and ZigBee signals, achieving significant improvements to Packet Loss/Delivery Rates relatively to conventional Amplify-and-Forward (LoRa PLR reduced by 23 times and ZigBee PDR increased by 8 times).
Accessing and interacting with difficult to reach surfaces at various orientations is of interest... more Accessing and interacting with difficult to reach surfaces at various orientations is of interest within a variety of industrial contexts. Thus far, the predominant robotic solution to such a problem has been to leverage the maneuverability of a fully actuated, omnidirectional aerial manipulator. Such an approach, however, requires a specialised system with a high relative degree of complexity, thus reducing platform endurance and real-world applicability. The work here presents a new aerial system composed of a parallel manipulator and conventional, underactuated multirotor flying base to demonstrate interaction with vertical and non-vertical surfaces. Our solution enables compliance to external disturbance on both subsystems, the manipulator and flying base, independently with a goal of improved overall system performance when interacting with surfaces. To achieve this behaviour, an admittance control strategy is implemented on various layers of the flying base's dynamics together with torque limits imposed on the manipulator actuators. Experimental evaluations show that the proposed system is compliant to external perturbations while allowing for differing interaction behaviours as compliance parameters of each subsystem are altered. Such capabilities enable an adjustable form of dexterity in completing sensor installation, inspection and aerial physical interaction tasks. A video of our system interacting with various surfaces can be found here: https://youtu.be/38neGb8-lXg.
Bone's homeostasis is only achieved when there is a balance between bone formation and bone r... more Bone's homeostasis is only achieved when there is a balance between bone formation and bone resorption. A metabolic disorder of bone-resorbing osteoclasts can lead to osteoporosis. Long-term use of anti-osteoporosis drugs can lead to undesirable side effects so traditional herbal can be a potential source of alternative medicine. In the present study, forty one Vietnamese plants (seventy methanol extracts) were screened for osteoclastogenesis inhibitory activities on RAW264.7 mouse macrophage cells. For the first time, 29 extracts from 24 species showed potential as effective inhibitors of osteoclastogenesis.
Allocating scarce resources with (weak) priority and complex constraints has many applications ra... more Allocating scarce resources with (weak) priority and complex constraints has many applications ranging from course allocation, and healthcare rationing to refugee resettlement. Its generality, however, mostly leads to impossibility results. We offer a positive result with a mechanism based on a new concept called competitive stable equilibrium. This is a natural extension of competitive equilibrium with endowed budgets that accommodates weak priorities. Specifically, an agent only needs to pay for a resource if it belongs to the last tier among the agents currently consuming the resource. This concept applies to both frameworks of one-sided and two-sided markets in a unifying way and allows for a more flexible tie-breaking rule by giving agents different budgets. We empirically apply our mechanism to reassign season tickets to families in the presence of social distancing. Our simulation results show that our method outperforms existing ones in both efficiency and fairness measures.
Proceedings of the AAAI Conference on Artificial Intelligence
We describe a tool, MatchMaps, that generates sameAs and partOf matches between spatial objects (... more We describe a tool, MatchMaps, that generates sameAs and partOf matches between spatial objects (such as shops, shopping centres, etc.) in crowd-sourced and authoritative geospatial datasets. MatchMaps uses reasoning in qualitative spatial logic, description logic and truth maintenance techniques, to produce a consistent set of matches. We report the results of an initial evaluation of MatchMaps by experts from Ordnance Survey (Great Britain’s National Mapping Authority). In both the case studies considered, MatchMaps was able to correctly match spatial objects (high precision and recall) with minimal human intervention.
Proceedings of the AAAI Conference on Artificial Intelligence
In many logic-based BDI agent programming languages, plan selection involves inferencing over som... more In many logic-based BDI agent programming languages, plan selection involves inferencing over some underlying knowledge representation. While context-sensitive plan selection facilitates the development of flexible, declarative programs, the overhead of evaluating repeated queries to the agent's beliefs and goals can result in poor run time performance. In this paper we present an approach to multi-cycle query caching for logic-based BDI agent programming languages. We extend the abstract performance model presented in (Alechina et al. 2012) to quantify the costs and benefits of caching query results over multiple deliberation cycles. We also present results of experiments with prototype implementations of both single- and multi-cycle caching in three logic-based BDI agent platforms, which demonstrate that significant performance improvements are achievable in practice.
Four neolignans, (7S,8S)-dihydrodehydrodiconiferyl alcohol 9-O-β-D-glucopyranoside (1), (7S,8S)-d... more Four neolignans, (7S,8S)-dihydrodehydrodiconiferyl alcohol 9-O-β-D-glucopyranoside (1), (7S,8S)-dihydrodehydrodiconiferyl alcohol 9′-O-β-D-glucopyranoside (2), (7S,8R)-5-methoxydihydrodehydrodiconiferyl alcohol 4-O-β-D-glucopyranoside (3), and (7S,8R)-5-methoxydihydrodehydrodiconiferyl alcohol 9′-O-β-D-glucopyranoside (4) and five flavonol glycosides, kaempferol-3-O-β-D-glucopyranoside (5), kaempferol 3-O-rutinoside (6), kaempferol 3-O-α-L-rhamnopyranosyl (1→6)-β-D-galactopyranoside (7), kaempferol 3-O-β-D-galactopyranoside (8), and quercetin 3-O-β-D-glucopyranoside (9) were isolated from the methanol extract of Viburnum lutescens Blume leaves. Their chemical structures were elucidated by 1D- and 2D-NMR spectra and comparison with those reported in the literature. Compounds 1, 2, and 4 were reported from Viburnum genus for the first time.
Wireless links are increasingly used to deliver critical services, while intentional interference... more Wireless links are increasingly used to deliver critical services, while intentional interference (jamming) remains a very serious threat to such services. In this paper, we are concerned with the design and evaluation of a universal anti-jamming building block, that is agnostic to the specifics of the communication link and can therefore be combined with existing technologies. We believe that such a block should not require explicit probes, sounding, training sequences, channel estimation, or even the cooperation of the transmitter. To meet these requirements, we propose an approach that relies on advances in Machine Learning, and the promises of neural accelerators and software defined radios. We identify and address multiple challenges, resulting in a convolutional neural network architecture and models for a multi-antenna system to infer the existence of interference, the number of interfering emissions and their respective phases. This information is continuously fed into an algorithm that cancels the interfering signal. We develop a twoantenna prototype system and evaluate our jamming cancellation approach in various environment settings and modulation schemes using Software Defined Radio platforms. We demonstrate that the receiving node equipped with our approach can detect a jammer with over 99% of accuracy and achieve a Bit Error Rate (BER) as low as 10 −6 even when the jammer power is nearly two orders of magnitude (18 dB) higher than the legitimate signal, and without requiring modifications to the link modulation. In non-adversarial settings, our approach can have other advantages such as detecting and mitigating collisions.
Innovative side-channel attacks have repeatedly exposed the secrets of cryptosystems. Benhamouda,... more Innovative side-channel attacks have repeatedly exposed the secrets of cryptosystems. Benhamouda, Degwekar, Ishai, and Rabin (CRYPTO–2018) introduced local leakage resilience of secret-sharing schemes to study some of these vulnerabilities. In this framework, the objective is to characterize the unintended information revelation about the secret by obtaining independent leakage from each secret share. This work accurately quantifies the vulnerability of the additive secret-sharing scheme to local leakage attacks and its consequences to other secret-sharing schemes. Consider the additive secret-sharing scheme over a prime field among k parties, where the secret shares are stored in their natural binary representation, requiring λ bits – the security parameter. We prove that the reconstruction threshold k = ω(log λ) is necessary to protect against local physical-bit probing attacks, improving the previous ω(log λ/ log log λ) lower bound. This result is a consequence of accurately dete...
As in many developing countries, landfill is considered to be the most suitable waste disposal me... more As in many developing countries, landfill is considered to be the most suitable waste disposal method in Vietnam. However, landfill and its related issues have caused a number of serious environmental conflicts. To manage the municipal waste disposed to landfill properly and effectively in order to minimize the associated pollutions and prolong the duration of landfill, it requires a comprehensive and challenging solution to those conflicts. Reducing the household waste, therefore, should be considered as prerequisite in solving these conflicts. Household waste unit pricing is proved in many countries to be an effective measure in reducing the household waste and improving people´s awareness of household waste management. In this thesis, an empirical research through a survey in the communities of all 6 urban districts of Da Nang city in Vietnam, where Khanh Son landfill located, is conducted. The survey focuses on general awareness of household waste of the people in these communit...
Secure multi-party computation (MPC) allows mutually distrusting parties to compute securely over... more Secure multi-party computation (MPC) allows mutually distrusting parties to compute securely over their private data. The hardness of MPC, essentially, lies in performing secure multiplications over suitable algebras. There are several cryptographic resources that help securely compute one multiplication over a large finite field, say GF [2 n ], with linear communication complexity. For example, the computational hardness assumption like noisy Reed-Solomon codewords are pseudorandom. However, it is not known if we can securely compute, say, a linear number of AND-gates from such resources, i.e., a linear number of multiplications over the base field GF [2]. Before our work, we could only perform o(n) secure AND-evaluations. Technically, we construct a perfectly secure protocol that realizes a linear number of multiplication gates over the base field using one multiplication gate over a degree-n extension field. This construction relies on the toolkit provided by algebraic function fields. Using this construction, we obtain the following results. We provide the first construction that computes a linear number of oblivious transfers with linear communication complexity from the computational hardness assumptions like noisy Reed-Solomon codewords are pseudorandom, or arithmetic-analogues of LPN-style assumptions. Next, we highlight the potential of our result for other applications to MPC by constructing the first correlation extractor that has 1/2 resilience and produces a linear number of oblivious transfers.
Proceedings of the 2019 ACM Conference on Economics and Computation, 2019
We consider a new model of many-to-one matching markets in which agents with multi-unit demand ai... more We consider a new model of many-to-one matching markets in which agents with multi-unit demand aim to maximize a cardinal linear objective subject to multidimensional knapsack constraints. The choice functions of agents with multi-unit demand are therefore not substitutable. As a result, pairwise stable matchings may not exist and, even when they do, may be highly inefficient. We provide an algorithm that finds a groupstable matching that approximately satisfies all the multidimensional knapsack constraints. The degree of the constraint violation is proportional to the sparsity of the constraint matrix. The algorithm therefore provides practical error bounds for applications in several contexts, such as refugee resettlement, matching of children to daycare centers, and meeting diversity requirements in colleges. A novel ingredient in our algorithm is a combination of matching with contracts and Scarf's Lemma. For full version of our paper, please see http://web.ics.purdue.edu/ nguye161/complexconstraint.pdf. CCS Concepts: • Social and professional topics; • Theory of computation → Algorithmic game theory and mechanism design;
An increasing number of organisations are turning to knowledge management (KM) as a key to levera... more An increasing number of organisations are turning to knowledge management (KM) as a key to leverage their distinctive core competencies in their pursuit of competitive advantage. Organisations are interested in KM to boost the efficiency of their processes, increase their productivity and quality of their services, and to achieve innovative solutions and products for their customers. Consequently, the contributions of KM to the overall success of an organisation have been widely acknowledged. Prior research studies have demonstrated that both organisational culture and leadership behaviours are widely held to be major barriers to creating and leveraging knowledge. The literature suggests that for KM implementation to be effective there is a need to diagnose the fit between an organisation and its KM objectives. Thus, it is essential to articulate how organisational culture and leadership styles affect the organisation’s ability to create and apply knowledge. It is only then that app...
In this paper, we introduce a new robust procedure to identify material parameters of mechanical ... more In this paper, we introduce a new robust procedure to identify material parameters of mechanical models from full-field measurements. It is based on data information coming from the Digital Image Correlation technique. The procedure aims at defining a suitable numerical processing, in terms of model selection and discretization mesh, with respect to information and noise contained in the data. The nature of the procedure is to minimize a cost functional based on the modified Constitutive Relation Error concept, which is made of modeling and measurement terms. Constructing an admissible stress field, verifying the equilibration equation in a full sense, enables one to obtain estimates on both discretization and modeling errors, which can then be compared with measurement noise in order to drive mesh adaptation and model enrichment. In addition, the procedure is coupled with reduced order modeling techniques in order to optimize computation costs. The overall approach is implemented o...
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