Flow Decomposition for Multi-User Channels - Part I

A framework based on the idea of flow decomposition is proposed to characterize the decode-forward region for general multi-source, multi-relay, all-cast channels with independent input distributions. The region is difficult to characterize directly when deadlocks occur between two relay nodes, in which both relays benefit by decoding after each other. Rate-vectors in the decode-forward region depend ambiguously on the outcomes of all deadlocks in the channel. The region is characterized indirectly in two phases. The first phase assumes relays can operate non-causally. It is shown that every rate-vector in the decode-forward region corresponds to a set of flow decompositions, which describe the messages decoded at each node with respect to the messages forwarded by all the other nodes. The second phase imposes causal restrictions on the relays. Given an arbitrary set of (possibly non-causal) flow decompositions, necessary and sufficient conditions are derived for the existence of an equivalent set of causal flow decompositions that achieves the same rate-vector region

Strategies for Scaleable Communication and Coordination in Multi-Agent (UAV) Systems

A system is considered in which agents (UAVs) must cooperatively discover interest-points (i.e., burning trees, geographical features) evolving over a grid. The objective is to locate as many interest-points as possible in the shortest possible time frame. There are two main problems: a control problem, where agents must collectively determine the optimal action, and a communication problem, where agents must share their local states and infer a common global state. Both problems become intractable when the number of agents is large. This survey/concept paper curates a broad selection of work in the literature pointing to a possible solution; a unified control/communication architecture within the framework of reinforcement learning. Two components of this architecture are locally interactive structure in the state-space, and hierarchical multi-level clustering for system-wide communication. The former mitigates the complexity of the control problem and the latter adapts to fundamental throughput constraints in wireless networks. The challenges of applying reinforcement learning to multi-agent systems are discussed. The role of clustering is explored in multi-agent communication. Research directions are suggested to unify these components

An Information Theoretic Framework for Two-Way Relay Networks

We propose an information theoretic framework for scheduling the transmissions in a two-way multi-hop network. First we investigate some long standing open problems that were encountered during the course of the research. To illustrate their difficulty, we describe some failed attempts at resolving them. We then introduce the two-way one-relay channel. It turns out that the achievable rate region of this network has a nice interpretation, especially when viewed in the context of the open problems examined earlier. Motivated by this observation, we attempt to extend this achievable region to the two-way two-relay channel. In the process, we expose a fundamental deadlock problem in which each relay needs to decode before the other in order to enable mutual assistance. Our most important contribution is a resolution to this deadlock problem; we add an additional constraint that ensures some relay can decode at least one message before the other relay. Furthermore, we also introduce several coding schemes to prove that the additional constraint is indeed sufficient. Our schemes also show that information theory provides unique insight into scheduling the transmissions of multi-hop networks

Mangrove Distribution and Morphology Changes in the Mullipallam Creek, South Eastern Coast of India

The Mangrove forest is globally important for the productivity of the coastal environment and is a good nursery site for aquatic organisms. The objective of the present paper was to create thematic maps of the wetland ecosystem and to analyse its changes, while making Remote Sensing and GIS techniques contributions to the Mullipallam region. Remotely sensed satellite data were used to detect changes in the mangrove cover for a period of 16 years (1991-2007). We found that an area of about 165.4 ha of dense mangrove degraded from 1999 to 2007 due to anthropogenic and shoreline erosion but sparse mangroves area significantly increased during this period due conservation and restoration activities. A Morphodynamics study (1929-2007) found that the migration of the River Cauvery tributaries in the wetland system had shifted towards the eastern side of the creek and the confluence of River Koraiyar had migrated towards the N-NNE direction. We observed that in recent decades mangrove forest have swiftly degraded because of intensified human activities

A Clean Slate Design for Secure Wireless Ad-Hoc Networks -Part 1: Closed Synchronized Networks

Abstract-We propose a clean-slate, holistic approach to the design of secure protocols for wireless ad-hoc networks. We design a protocol that enables a collection of distributed nodes to emerge from a primordial birth and form a functioning network. We consider the case when nodes are synchronized and the network is closed, in that no other nodes can join. We define a game between protocols and adversarial nodes, and describe a protocol that is guaranteed to achieve the max-min payoff regardless of what the adversarial nodes do. Moreover, even though the adversarial nodes always know the protocol a priori, we show an even stronger result; the protocol is guaranteed to achieve the min-max payoff. Hence there is a saddle point in the game between protocols and adversarial strategies. Finally, we show that the adversarial nodes are in effect, strategically confined to either jamming or conforming to the protocol. These guarantees are contingent on a set of underlying model assumptions, and cease to be valid if the assumptions are violated

NC2213: a novel methionine aminopeptidase 2 inhibitor in human colon cancer HT29 cells

Methionine aminopeptidase 2 (MetAP2) is a bifunctional protein that plays a critical role in the regulation of post-translational processing and protein synthesis. MetAP2 is overexpressed in human colon cancer. In this report we screened various MetAP2 inhibitors and treated HT29 cells with various concentrations of compounds. We evaluated the expression of MetAP2 and pp60c-src expressions in HT29 cells. In addition we also carried out the cell proliferation and cell cycle analysis in the MetAP2 inhibitor-treated HT29 cells. The cell cycle analysis of HT29 treated with 1.0 μM of NC2213 showed an arrest in the G2 phase followed by an induction in the percentage of cells undergoing apoptosis in the sub-G1 phase. Western blot analysis revealed that the MetAP2 expression was dose-dependently decreased when the HT29 cells were treated with the 3,5-bis(benzylidene)-4-piperidone derivative (NC2213). In addition, phosphorylation of Src, a myristoylated oncoprotein was significantly decreased by 1.0 μM of NC2213 as revealed by Western blot analysis. Furthermore, NC2213 also inhibits the expression of pp60c-src in HT29 cells. Interestingly, this compound also inhibits the phosphorylation at Tyr416 of pp60c-src while increasing the phosphorylation at Tyr527 of pp60c-src. NC2213 inhibits the growth of HT29 cells by inducing apoptosis and might be useful for the treatment of human colon cancer

A System-Theoretic Clean Slate Approach to Provably Secure Ad Hoc Wireless Networking

Abstract-Traditionally, wireless network protocols have been designed for performance. Subsequently, as attacks have been identified, patches have been developed. This has resulted in an "arms race" development process of discovering vulnerabilities and then patching them. The fundamental difficulty with this approach is that other vulnerabilities may still exist. No provable security or performance guarantees can ever be provided. We develop a system-theoretic approach to security that provides a complete protocol suite with provable guarantees, as well as proof of min-max optimality with respect to any given utility function of source-destination rates. Our approach is based on a model capturing the essential features of an adhoc wireless network that has been infiltrated with hostile nodes. We consider any collection of nodes, some good and some bad, possessing specified capabilities vis-a-vis cryptography, wireless communication and clocks. The good nodes do not know the bad nodes. The bad nodes can collaborate perfectly, and are capable of any disruptive acts ranging from simply jamming to non-cooperation with the protocols in any manner they please. The protocol suite caters to the complete life-cycle, all the way from birth of nodes, through all phases of ad hoc network formation, leading to an optimized network carrying data reliably. It provably achieves the min-max of the utility function, where the max is over all protocol suites published and followed by the good nodes, while the min is over all Byzantine behaviors of the bad nodes. Under the protocol suite, the bad nodes do not benefit from any actions other than jamming or cooperating. This approach supersedes much previous work that deals with several types of attacks including wormhole, rushing, partial deafness, routing loops, routing black holes, routing gray holes, and network partition attacks

Increasing incidence of spondylodiscitis in England: an analysis of the national health service (NHS) hospital episode statistics from 2012 to 2021

Background Spondylodiscitis is a potentially life-threatening infection of the intervertebral disk and adjacent vertebral bodies, with a mortality rate of 2–20%. Given the aging population, the increase in immunosuppression, and intravenous drug use in England, the incidence of spondylodiscitis is postulated to be increasing; however, the exact epidemiological trend in England remains unknown. Objective The Hospital Episode Statistics (HES) database contains details of all secondary care admissions across NHS hospitals in England. This study aimed to use HES data to characterise the annual activity and longitudinal change of spondylodiscitis in England. Methods The HES database was interrogated for all cases of spondylodiscitis between 2012 and 2019. Data for the length of stay, waiting time, age-stratified admissions, and ‘Finished Consultant Episodes’ (FCEs), which correspond to a patient's hospital care under a lead clinician, were analysed. Results In total, 43135 FCEs for spondylodiscitis were identified between 2012 and 2022, of which 97.1% were adults. Overall admissions for spondylodiscitis have risen from 3 per 100,000 population in 2012/13 to 4.4 per 100,000 population in 2020/21. Similarly, FCEs have increased from 5.8 to 10.3 per 100,000 population, in 2012–2013 and 2020/21 respectively. The highest increase in admissions from 2012 to 2021 was recorded for those aged 70–74 (117% increase) and aged 75-59 (133% increase), among those of working age for those aged 60–64 years (91% increase). Conclusion Population-adjusted admissions for spondylodiscitis in England have risen by 44% between 2012 and 2021. Healthcare policymakers and providers must acknowledge the increasing burden of spondylodiscitis and make spondylodiscitis a research priority

Conservative versus early surgical treatment in the management of pyogenic spondylodiscitis: a systematic review and meta-analysis [Abstract]

Oral e-Poster Presentations - Booth 2: Spine 1 (Trauma&Misc), September 25, 2023, 10:00 AM - 10:40 AM Background: Spondylodiscitis is a prevalent type of spinal infection, with pyogenic spondylodiscitis being the most common subtype. While antibiotic therapy is the standard treatment, some argue that early surgery can aid in infection clearance, improve survival rates, and prevent long-term complications such as deformities. However, others view early surgery as excessively risky. Due to the high mortality rate of up to 20%, it is crucial to determine the most effective treatment. Methods: The primary objective of this study was to compare the mortality rate, relapse rate, and length of hospital stay for conservative and early surgical treatments of pyogenic spondylodiscitis, including determinants of outcomes. The study was registered on PROSPERO with the registration number CRD42022312573. The databases MEDLINE, Embase, Scopus, PubMed, and JSTOR were searched for original studies comparing conservative and early surgical treatments of pyogenic spondylodiscitis. The included studies were assessed using the ROBINS-1 tool, and eligible studies were evaluated using meta-analyses, influence, and regression analyses. Results: The systematic review included 31 studies. The meta-analysis, which had a pooled sample size of 10,954 patients from 21 studies, found that the pooled mortality rate among patients treated with early surgery was 8%, while the rate was 13% for patients treated conservatively. The mean proportion of relapse/failure was 15% for patients treated with early surgery and 21% for those treated conservatively. Furthermore, the analysis concluded that early surgical treatment is associated with a 40% and 39% risk reduction in relapse/failure and mortality rates, respectively, when compared to conservative management. Additionally, early surgical treatment resulted in a 7.75-day reduction in length of hospital stay per patient (p<0.01). The most highly significant predictors of treatment outcome were found to be intravenous drug use, diabetes, the presence of an epidural abscess, positive cultures, location of infection, and age (p<0.001). Conclusions: Overall, early surgical management was found to be consistently significantly more effective than conservative management in terms of relapse/failure and mortality rates when treating pyogenic spondylodiscitis, particularly for non-spinal epidural abscess spondylodiscitis