Linearly constrained optimization

For linearly constrained optimization problems an algorithm is presented which is based on conjugate gradients. Numerical tests demonstrate a favourable behaviour of the new algorithm.     

Prediction Mechanisms to Improve 5G Network User Allocation and Resource Management

As technology rapidly advances, the number of devices constantly communicating, transmitting and receiving data through the cellular networks keeps rising, posing an unprecedented load on them. Such an increase calls for establishing new methods to manage these devices as well as utilize the data produced by them to establish network architectures that can prevent cellular networks from overloading. To achieve the desired results, we need to optimally allocate network resources to existing users. Resource allocation has traditionally been considered an optimization problem where proposed solutions are hard to implement in real time, resulting in the use of inferior solutions with reduced produced performance. With the introduction of Machine Learning, we propose three mechanisms, intending to utilize network data to improve real time network performance. The first mechanism, a Decision Trees based mechanism aims to improve real time decision making by predicting the optimal matching of users and Base Stations. The second mechanism, a K-means based mechanism intends to tackle network congestion and ensure uninterrupted Quality of Service by predicting the optimal coordinates for placing Base Stations along the network based on traffic data. Finally, a Regression based mechanism manages to predict user movement along the network, resulting in improved resource management and reduced energy waste. These mechanisms can work cooperatively, essentially establishing a network architecture that utilizes prediction to efficiently allocate users and manage available resources.

     

Electrically conductive thermosetting resins containing low concentrations of carbon black

A cured vinyl ester resin containing electrically conductive carbon black (CB) particles shows electrical percolation at very low CB concentration (<0.5 phr). CB particles have a strong tendency to agglomerate in a low‐viscosity resin, such as vinyl ester, unsaturated polyester resin, and epoxy resins. The agglomeration process in the low‐viscosity vinyl ester resin generates electrically conductive paths already in the resin's liquid state, which undergo partial fixation by room temperature curing and full fixation by hot postcuring. The fully cured castings containing CB concentrations above percolation are characterized by a constant, temperature‐independent conductivity, over a wide temperature range. The current–voltage relationships of the cured vinyl ester/CB castings obey a power‐law dependency. The presence of the continuous CB paths in the vinyl ester casting is clearly observed in fracture surfaces formed at 100°C. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1165–1170, 2000     

Two-stage optimization problem with chance constraints

In general, chemical processes (CP) are designed with the use of inaccurate mathematical models. Therefore, it is important to create a chemical process that guarantees satisfaction of all design specifications either exactly or with some probability. The paper considers the issue of chemical process optimization when at the operation stage the design specification should be met with some probability and the control variables can be changed. We developed a new formulation of the two-stage optimization problem (TSOP) with chance constraints. On the basis of this formulation and approximate transformation of chance constraints into deterministic ones the iteration method of solving the TSOP with chance constraints is devised.     

Perfect Zero-Knowledge Arguments for NP Using Any One-Way Permutation

``Perfect zero-knowledge arguments' is a cryptographic primitive which allows one polynomial-time player to convince another polynomial-time player of the validity of an NP statement, without revealing any additional information (in the information-theoretic sense). Here the security achieved is on-line: in order to cheat and validate a false theorem, the prover must break a cryptographic assumption on-line during the conversation, while the verifier cannot find (ever) any information unconditionally. Despite their practical and theoretical importance, it was only known how to implement zero-knowledge arguments based on specific algebraic assumptions. In this paper we show a general construction which can be based on any one-way permutation. The result is obtained by a construction of an information-theoretic secure bit-commitment protocol. The protocol is efficient (both parties are polynomial time) and can be based on any one-way permutation. Received 5 September 1993 and revised 16 September 1997     

Antithrombin III prevents and rapidly reverses leukocyte recruitment in ischemia/reperfusion

BACKGROUND: P-selectin has recently been shown to be essential for leukocyte rolling after the reperfusion of ischemic mesentery. However, the mediators responsible for neutrophil rolling in ischemic microvessels remain entirely unclear. METHODS AND RESULTS: Intravital microscopy was used to examine leukocyte kinetics in a feline mesentery ischemia/reperfusion model. Sixty minutes of ischemia followed by reperfusion caused a profound increase in leukocyte rolling and adhesion. Pretreatment with the endogenous antithrombotic agent antithrombin III (ATIII) infused as a bolus (250 U/kg) reduced neutrophil rolling and adhesion to preischemic levels during reperfusion. No effect was seen with heat-inactive ATIII. Importantly, ATIII posttreatment also significantly reduced neutrophil rolling and adhesion during reperfusion, suggesting that ATIII can reverse the leukocyte recruitment response induced by ischemia/reperfusion. Vascular permeability was also reduced by 50% after ATIII administration. To determine whether ATIII could reverse thrombin-induced rolling directly, neutrophil rolling was performed on human endothelium in flow chambers. Indeed, thrombin-induced rolling, but not histamine-induced rolling, could be rapidly reversed with ATIII on endothelium, suggesting that ATIII affects thrombin rather than directly affecting neutrophils or the endothelium. CONCLUSIONS: This study demonstrates for the first time that thrombin plays an important role in ischemia-induced leukocyte rolling and adhesion and that ATIII can be used therapeutically postreperfusion to attenuate the leukocyte recruitment response in inflammation without the nonspecific effects associated with anti-adhesion molecule therapy.     

Almost-Everywhere Secure Computation with Edge Corruptions

We consider secure multi-party computation (MPC) in a setting where the adversary can separately corrupt not only the parties (nodes) but also the communication channels (edges), and can furthermore choose selectively and adaptively which edges or nodes to corrupt. Note that if an adversary corrupts an edge, even if the two nodes that share that edge are honest, the adversary can control the link and thus deliver wrong messages to both players. We consider this question in the information-theoretic setting, and require security against a computationally unbounded adversary.In a fully connected network the above question is simple (and we also provide an answer that is optimal up to a constant factor). What makes the problem more challenging is to consider the case of sparse networks. Partially connected networks are far more realistic than fully connected networks, which led Garay and Ostrovsky [Eurocrypt’08] to formulate the notion of (unconditional) almost everywhere (a.e.) secure computation in the node-corruption model, i.e., a model in which not all pairs of nodes are connected by secure channels and the adversary can corrupt some of the nodes (but not the edges). In such a setting, MPC among all honest nodes cannot be guaranteed due to the possible poor connectivity of some honest nodes with other honest nodes, and hence some of them must be “given up” and left out of the computation. The number of such nodes is a function of the underlying communication graph and the adversarial set of nodes.In this work we introduce the notion of almost-everywhere secure computation with edge corruptions, which is exactly the same problem as described above, except that we additionally allow the adversary to completely control some of the communication channels between two correct nodes—i.e., to “corrupt” edges in the network. While it is easy to see that an a.e. secure computation protocol for the original node-corruption model is also an a.e. secure computation protocol tolerating edge corruptions (albeit for a reduced fraction of edge corruptions with respect to the bound for node corruptions), no polynomial-time protocol is known in the case where a constant fraction of the edges can be corrupted (i.e., the maximum that can be tolerated) and the degree of the network is sublinear.We make progress on this front, by constructing graphs of degree O(n ^? ) (for arbitrary constant 0<?<1) on which we can run a.e. secure computation protocols tolerating a constant fraction of adversarial edges. The number of given-up nodes in our construction is μn (for some constant 0<μ<1 that depends on the fraction of corrupted edges), which is also asymptotically optimal.