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Rohit Negi

Publications and source records attributed to Rohit Negi.

At least 19 recordsLinked to original sources

ReCon: A Resource-Constrained Benchmark for LLM-Based Cybersecurity Compliance Across Ingestion and Retrieval Pipelines

With the increasingly aggressive cyber threat landscape for governments, businesses, and institutions, as information and/or cybersecurity implementations are increasingly under scrutiny by regulators, it has been pointed out that governance failure is one of the major reasons for a weakened cybersecurity posture. A major component of Cyber/information security governance is the development, adoption, and implementation of a comprehensive information and/or cyber security policy document. The policy document must be in compliance with international or national standards and, if possible, with regulatory guidelines. However, it is often observed that policy documents are often incomplete with respect to industry standards or regulations and require revision when subjected to a thorough audit. Identifying the gaps between the controls and processes documented in the policy and those required in the regulations or standards necessitates extensive manual effort. The advent of Generative AI tools such as Large Language Models (LLMs) led to use of LLMs and Agentic AI tools to automate such compliance checks, as seen in a few research publications in recent times. However, such reported use of LLMs are experimented with high resource environments such as expensive GPUs and memory based servers. For smaller organizations such expensive compute platform may not be easily available. In this article, we benchmark the compliance checking tasks on LLMs that do not require GPU and high memory usage and the effectiveness of such resource constrained LLMs in compliance checking. Our experiments demonstrated that the low resource LLMs can provide good agreement/accuracy in compliance checking of policy documents against standards by experimenting with ISO 27002:2022 controls against multiple policy documents.

cs.CR

An Optimization Framework for Certain Separable Problems using Neural Networks

This paper studies a class of parametric constrained optimization problems that are motivated by applications in real time applications. Under a parameter-separable problem structure that naturally arises in these applications, the paper proposes a two phase strategy, based on offline learning and online processing, to address these optimization problems on resource limited devices. Specifically, by exploiting the separable structure, an iterative Alternating Direction Method of Multipliers (ADMM) based solution procedure is developed that enables the use of certain learning based function representations (learned offline but readily computable online) to reduce the overall online on-device implementation complexity. By carefully crafting the ADMM procedure, it is shown that even as the parameters vary, the corresponding instances of the parametric optimization problem may be solved by lightweight online computations in the device with the assistance of a neural network co-processor.

eess.SP

Optimal Scheduling in a Question-Answering Forum of Knowledge Workers

As individuals turn to the Internet to find answers to questions they may have, several Question Answering (QA) forums have evolved, where users knowledgeable in certain topics can contribute their expertise to answering these requests for information. While these are currently volunteer based, we consider a future version employing knowledge workers who are experts in certain topics. In such a system, the request-answer processes forming the queuing system may utilize schedulers that assign requests in different topics to the experts in the forum, who may be able to answer them according to their expertise levels in different topics. With this model, we calculate the capacity of the system for handling the requests while keeping the system stable, and design schedulers that achieve capacity. We also investigate how collaboration between experts in answering requests can potentially increase capacity.

cs.AI

Cyber security of Mega Events: A Case Study of Securing the Digital Infrastructure for MahaKumbh 2025 -- A 45 days Mega Event of 600 Million Footfalls

Mega events such as the Olympics, World Cup tournaments, G-20 Summit, religious events such as MahaKumbh are increasingly digitalized. From event ticketing, vendor booth or lodging reservations, sanitation, event scheduling, customer service, crime reporting, media streaming and messaging on digital display boards, surveillance, crowd control, traffic control and many other services are based on mobile and web applications, wired and wireless networking, network of Closed-Circuit Television (CCTV) cameras, specialized control room with network and video-feed monitoring. Consequently, cyber threats directed at such digital infrastructure are common. Starting from hobby hackers, hacktivists, cyber crime gangs, to the nation state actors, all target such infrastructure to unleash chaos on an otherwise smooth operation, and often the cyber threat actors attempt to embarrass the organizing country or the organizers. Unlike long-standing organizations such as a corporate or a government department, the infrastructure of mega-events is temporary, constructed over a short time span in expediency, and often shortcuts are taken to make the deadline for the event. As a result, securing such an elaborate yet temporary infrastructure requires a different approach than securing a standard organizational digital infrastructure. In this paper, we describe our approach to securing MahaKumbh 2025, a 600 million footfall event for 45 days in Prayagraj, India, as a cyber security assessment and risk management oversight team. We chronicle the scope, process, methodology, and outcome of our team's effort to secure this mega event. It should be noted that none of the cyber attacks during the 45-day event was successful. Our goal is to put on record the methodology and discuss what we would do differently in case we work on similar future mega event.

cs.CR

Security Orchestration, Automation, and Response Engine for Deployment of Behavioural Honeypots

Cyber Security is a critical topic for organizations with IT/OT networks as they are always susceptible to attack, whether insider or outsider. Since the cyber landscape is an ever-evolving scenario, one must keep upgrading its security systems to enhance the security of the infrastructure. Tools like Security Information and Event Management (SIEM), Endpoint Detection and Response (EDR), Threat Intelligence Platform (TIP), Information Technology Service Management (ITSM), along with other defensive techniques like Intrusion Detection System (IDS), Intrusion Protection System (IPS), and many others enhance the cyber security posture of the infrastructure. However, the proposed protection mechanisms have their limitations, they are insufficient to ensure security, and the attacker penetrates the network. Deception technology, along with Honeypots, provides a false sense of vulnerability in the target systems to the attackers. The attacker deceived reveals threat intel about their modus operandi. We have developed a Security Orchestration, Automation, and Response (SOAR) Engine that dynamically deploys custom honeypots inside the internal network infrastructure based on the attacker's behavior. The architecture is robust enough to support multiple VLANs connected to the system and used for orchestration. The presence of botnet traffic and DDOS attacks on the honeypots in the network is detected, along with a malware collection system. After being exposed to live traffic for four days, our engine dynamically orchestrated the honeypots 40 times, detected 7823 attacks, 965 DDOS attack packets, and three malicious samples. While our experiments with static honeypots show an average attacker engagement time of 102 seconds per instance, our SOAR Engine-based dynamic honeypots engage attackers on average 3148 seconds.

cs.CR

A Theoretical Framework for Online Information Search

A significant part of human activity today consists of searching for a piece of information online, utilizing knowledge repositories. This endeavor may be time-consuming if the individual searching for the information is unfamiliar with the subject matter of that information. However, experts can aid individuals find relevant information by searching online. This paper describes a theoretical framework to model the dynamic process by which requests for information come to a system of experts, who then answer the requests by searching for those pieces of information.

cs.IR

Supermajority Sentiment Detection with External Influence in Large Social Networks

In a large social network whose members harbor binary sentiments towards an issue, we investigate the asymptotic accuracy of sentiment detection. We model the user sentiments by an Ising Markov random field model and allow the user sentiments to be biased by an external influence. We consider a general supermajority sentiment detection problem and show that the detection accuracy is affected by the network structure, its parameters, as well as the external influence level.

cs.SI

Asymptotic Performance Analysis of Majority Sentiment Detection in Online Social Networks

We analyze the problem of majority sentiment detection in Online Social Networks (OSN), and relate the detection error probability to the underlying graph of the OSN. Modeling the underlying social network as an Ising Markov random field prior based on a given graph, we show that in the case of the empty graph (independent sentiments) and the chain graph, the detection is always inaccurate, even when the number of users grow to infinity. In the case of the complete graph, the detection is inaccurate if the connection strength is below a certain critical value, while it is asymptotically accurate if the strength is above that critical value, which is analogous to the phase transition phenomenon in statistical physics.

cs.SI

Latent Sentiment Detection in Online Social Networks: A Communications-oriented View

In this paper, we consider the problem of latent sentiment detection in Online Social Networks such as Twitter. We demonstrate the benefits of using the underlying social network as an Ising prior to perform network aided sentiment detection. We show that the use of the underlying network results in substantially lower detection error rates compared to strictly features-based detection. In doing so, we introduce a novel communications-oriented framework for characterizing the probability of error, based on information-theoretic analysis. We study the variation of the calculated error exponent for several stylized network topologies such as the complete network, the star network and the closed-chain network, and show the importance of the network structure in determining detection performance.

cs.SI

A Queueing Based Scheduling Approach to Plug-In Electric Vehicle Dispatch in Distribution Systems

Large-scale integration of plug-in electric vehicles (PEV) in power systems can cause severe issues to the existing distribution system, such as branch congestions and significant voltage drops. As a consequence, smart charging strategies are crucial for the secure and reliable operation of the power system. This paper tries to achieve high penetration level of PEVs with the existing distribution system infrastructure by proposing a smart charging algorithm that can optimally utilize the distribution system capacity. Specifically, the paper proposes a max-weight PEV dispatch algorithm to control the PEV charging rates, subject to power system physical limits. The proposed max-weight PEV dispatch algorithm is proved to be throughput optimal under very mild assumptions on the stochastic dynamics in the system. This suggests that the costly distribution system infrastructure upgrade can be avoided, or failing that, at least successfully deferred. The proposed PEV dispatch algorithm is particularly attractive in integrating the renewable energy sources in the distribution system, by successfully absorbing their intermittency.

math.OC

An Information-Theoretic Approach to PMU Placement in Electric Power Systems

This paper presents an information-theoretic approach to address the phasor measurement unit (PMU) placement problem in electric power systems. Different from the conventional 'topological observability' based approaches, this paper advocates a much more refined, information-theoretic criterion, namely the mutual information (MI) between the PMU measurements and the power system states. The proposed MI criterion can not only include the full system observability as a special case, but also can rigorously model the remaining uncertainties in the power system states with PMU measurements, so as to generate highly informative PMU configurations. Further, the MI criterion can facilitate robust PMU placement by explicitly modeling probabilistic PMU outages. We propose a greedy PMU placement algorithm, and show that it achieves an approximation ratio of (1-1/e) for any PMU placement budget. We further show that the performance is the best that one can achieve in practice, in the sense that it is NP-hard to achieve any approximation ratio beyond (1-1/e). Such performance guarantee makes the greedy algorithm very attractive in the practical scenario of multi-stage installations for utilities with limited budgets. Finally, simulation results demonstrate near-optimal performance of the proposed PMU placement algorithm.

math.OC

Maximal Scheduling in Wireless Networks with Priorities

We consider a general class of low complexity distributed scheduling algorithms in wireless networks, maximal scheduling with priorities, where a maximal set of transmitting links in each time slot are selected according to certain pre-specified static priorities. The proposed scheduling scheme is simple, which is easily amendable for distributed implementation in practice, such as using inter-frame space (IFS) parameters under the ubiquitous 802.11 protocols. To obtain throughput guarantees, we first analyze the case of maximal scheduling with a fixed priority vector, and formulate a lower bound on its stability region and scheduling efficiency. We further propose a low complexity priority assignment algorithm, which can stabilize any arrival rate that is in the union of the lower bound regions of all priorities. The stability result is proved using fluid limits, and can be applied to very general stochastic arrival processes. Finally, the performance of the proposed prioritized maximal scheduling scheme is verified by simulation results.

cs.IT

On-line Decentralized Charging of Plug-In Electric Vehicles in Power Systems

The concept of plug-in electric vehicles (PEV) are gaining increasing popularity in recent years, due to the growing societal awareness of reducing greenhouse gas (GHG) emissions, and gaining independence on foreign oil or petroleum. Large-scale deployment of PEVs currently faces many challenges. One particular concern is that the PEV charging can potentially cause significant impacts on the existing power distribution system, due to the increase in peak load. As such, this work tries to mitigate the impacts of PEV charging by proposing a decentralized smart PEV charging algorithm to minimize the distribution system load variance, so that a `flat' total load profile can be obtained. The charging algorithm is myopic, in that it controls the PEV charging processes in each time slot based entirely on the current power system states, without knowledge about future system dynamics. We provide theoretical guarantees on the asymptotic optimality of the proposed charging algorithm. Thus, compared to other forecast based smart charging approaches in the literature, the charging algorithm not only achieves optimality asymptotically in an on-line, and decentralized manner, but also is robust against various uncertainties in the power system, such as random PEV driving patterns and distributed generation (DG) with highly intermittent renewable energy sources.

math.OC

Distributed Throughput-optimal Scheduling in Ad Hoc Wireless Networks

In this paper, we propose a distributed throughput-optimal ad hoc wireless network scheduling algorithm, which is motivated by the celebrated simplex algorithm for solving linear programming (LP) problems. The scheduler stores a sparse set of basic schedules, and chooses the max-weight basic schedule for transmission in each time slot. At the same time, the scheduler tries to update the set of basic schedules by searching for a new basic schedule in a throughput increasing direction. We show that both of the above procedures can be achieved in a distributed manner. Specifically, we propose an average consensus based link contending algorithm to implement the distributed max weight scheduling. Further, we show that the basic schedule update can be implemented using CSMA mechanisms, which is similar to the one proposed by Jiang et al. Compared to the optimal distributed scheduler in Jiang's paper, where schedules change in a random walk fashion, our algorithm has a better delay performance by achieving faster schedule transitions in the steady state. The performance of the algorithm is finally confirmed by simulation results.

cs.IT

Greedy Maximal Scheduling in Wireless Networks

In this paper we consider greedy scheduling algorithms in wireless networks, i.e., the schedules are computed by adding links greedily based on some priority vector. Two special cases are considered: 1) Longest Queue First (LQF) scheduling, where the priorities are computed using queue lengths, and 2) Static Priority (SP) scheduling, where the priorities are pre-assigned. We first propose a closed-form lower bound stability region for LQF scheduling, and discuss the tightness result in some scenarios. We then propose an lower bound stability region for SP scheduling with multiple priority vectors, as well as a heuristic priority assignment algorithm, which is related to the well-known Expectation-Maximization (EM) algorithm. The performance gain of the proposed heuristic algorithm is finally confirmed by simulations.

cs.IT

Scheduling in Wireless Networks under Uncertainties: A Greedy Primal-Dual Approach

This paper proposes a dynamic primal-dual type algorithm to solve the optimal scheduling problem in wireless networks subject to uncertain parameters, which are generated by stochastic network processes such as random packet arrivals, channel fading, and node mobilities. The algorithm is a generalization of the well-known max-weight scheduling algorithm proposed by Tassiulas et al., where only queue length information is used for computing the schedules when the arrival rates are uncertain. Using the technique of fluid limits, sample path convergence of the algorithm to an arbitrarily close to optimal solution is proved, under the assumption that the Strong Law of Large Numbers (SLLN) applies to the random processes which generate the uncertain parameters. The performance of the algorithm is further verified by simulation results. The method may potentially be applied to other applications where dynamic algorithms for convex problems with uncertain parameters are needed.

cs.IT

Scheduling in Multi-hop Wireless Networks with Priorities

In this paper we consider prioritized maximal scheduling in multi-hop wireless networks, where the scheduler chooses a maximal independent set greedily according to a sequence specified by certain priorities. We show that if the probability distributions of the priorities are properly chosen, we can achieve the optimal (maximum) stability region using an i.i.d random priority assignment process, for any set of arrival processes that satisfy Law of Large Numbers. The pre-computation of the priorities is, in general, NP-hard, but there exists polynomial time approximation scheme (PTAS) to achieve any fraction of the optimal stability region. We next focus on the simple case of static priority and specify a greedy priority assignment algorithm, which can achieve the same fraction of the optimal stability region as the state of art result for Longest Queue First (LQF) schedulers. We also show that this algorithm can be easily adapted to satisfy delay constraints in the large deviations regime, and therefore, supports Quality of Service (QoS) for each link.

cs.IT

The Sensing Capacity of Sensor Networks

This paper demonstrates fundamental limits of sensor networks for detection problems where the number of hypotheses is exponentially large. Such problems characterize many important applications including detection and classification of targets in a geographical area using a network of sensors, and detecting complex substances with a chemical sensor array. We refer to such applications as largescale detection problems. Using the insight that these problems share fundamental similarities with the problem of communicating over a noisy channel, we define a quantity called the sensing capacity and lower bound it for a number of sensor network models. The sensing capacity expression differs significantly from the channel capacity due to the fact that a fixed sensor configuration encodes all states of the environment. As a result, codewords are dependent and non-identically distributed. The sensing capacity provides a bound on the minimal number of sensors required to detect the state of an environment to within a desired accuracy. The results differ significantly from classical detection theory, and provide an ntriguing connection between sensor networks and communications. In addition, we discuss the insight that sensing capacity provides for the problem of sensor selection.

cs.IT