Key Infrastructure Research Articles

Replay with Feedback: How does the performance of HPC system impact user submission behavior?

High Performance Computing (HPC) is a key infrastructure to solve large scale scientific problems, from weather to quantum simulations. Scheduling jobs in HPC infrastructures is complex due to their scale, the different behaviors of their users, and the multiple objectives, from performance to ecological impact. Schedulers are evaluated on data center simulations, due to the complexity and cost of evaluating them in-situ. One key element for this evaluation is the behavioral model of users. Most studies are limited to replaying past workload of existing data centers. This reduces the realism of performance evaluation in cases where the scheduler and the hardware infrastructure are not exactly the same. Any such change would potentially impact the behavior of the users.In this article we introduce a novel model “Replay with Feedback” accounting for the impact of HPC system performances on user submission behavior in simulations. Instead of keeping the original timestamps of job submissions, we exhibit and use the relationships between each user jobs. We propose an open-source implementation of this model along with an extensive and reproducible set of experiments to assess the impact of the scheduler and infrastructure changes. We also provide new metrics adapted to the flexibility of user submission behaviors. Results show that using this model, we advance towards more realistic simulations of schedulers in HPC systems.

Development of hybrid heuristic‐assisted dynamic data auditing strategy in cloud sector

AbstractCloud computing is performed by hosting the data of data owners on cloud servers, where the data consumers (users) are able to get the data over servers. Though, several security aspects are raised during cloud storage regarding the data availability and data integrity. On the other hand, a novel scheme of data hosting services is introduced owing to data outsourcing which also raises additional security problems. In addition, several methods are presented by taking either “identity‐based cryptography (IBC) or public key infrastructure (PKI).” Hence, a secure and effective dynamic data auditing scheme is preferable for convincing data owners to ensure precise data storage in the cloud. This paper focuses on implementing a new hybrid heuristic‐assisted strategy for managing cloud storage with the help of efficient auditing schemes. This paper tries to optimize the data structures in the cloud storage with a new improved hybrid differential evolution‐teamwork optimization algorithm (HED‐TOA) with the integration of the teamwork optimization algorithm (TOA) and differential evolution (DE) algorithms. It aims to alleviate the problems raised during the dynamic data update operations including “insert, modify, delete, and append.” This improved HED‐TOA help in performing the data auditing. This model overcomes the problem of modifications occurring in the data structure while doing the dynamic data update operations and thus, it ensures efficient data auditing and data management in cloud computing. This work considers the aim of reducing computation as well as communication costs during the data storage process in the cloud. The performance estimation demonstrates that there is considerable contrast between the traditional methods and the proposed technique in terms of the communication and computation cost on the cloud and auditor.

RETINA: Distributed and secure trust management for smart grid applications and energy trading

The rapid adoption of smart grids demands robust security and efficiency measures due to their critical role in delivering electricity and their potential for customer-oriented benefits. This article presents an innovative framework, named RETINA, which provides a resilient and secure energy trading mechanism within smart grid systems. RETINA tackles the inherent security and infrastructure challenges in smart grids by establishing a trust-based security layer and facilitating energy transactions through blockchain technology. Our proposed solution integrates Public Key Infrastructure (PKI) and the Web of Trust (WoT) concepts, promoting decentralized communication channels and robust key management. We further introduce a smart contract-based energy trading mechanism that factors trust, distance, and energy type (green or non-green) in the cost calculation. The utility and robustness of RETINA have been validated in a virtualized testbed environment with 500 nodes, demonstrating superior performance in terms of scalability and resilience compared to the existing WoT scheme. Furthermore, RETINA successfully enables a secure and efficient energy trading scheme, promoting the use of renewable energy sources and promptly recovering from market manipulation attacks. Future enhancements will include applying it to a realistic smart grid deployment and integrating additional functionalities. This groundbreaking solution can potentially revolutionize the smart grid ecosystem, addressing its current limitations and propelling the industry toward a future of advanced and secure energy exchange.

Road bridges exposure and alternative routes: towards the definition of road network resilience

The road network represents both element-at-risk and key infrastructure to ensure the accessibility of peripheral areas. The overall risk levels of bridges depend on geophysical (mainly earthquakes and landslides) and hydrometeorological hazards (mainly floods), the physical vulnerability of structures, and the exposure (mainly resulting from traffic flows and the presence of alternative roads). In mountain contexts and peripheral territories, the accessibility of entire territorial system directly depends on few trunk and secondary roads. The risk assessment of bridges, according to the Ministerial Guidelines, provides inputs for a territorial risk assessment starting from the accessibility of peripheral territories and the redundancy of the road network as features to determine the resilience of the road network. This study aims at understanding the relationships between bridges as elements-at-risk part of the road network and the influence they have on the overall accessibility of a territory. In this study, through a GIS analysis of a set of selected roads of the Provinces of Caserta (Campania Region), the presence of bridges along the selected roads have been combined with data on the accessibility levels of municipalities they connect. At this purpose, reference to the classification provided by the National Strategy for Inner Areas (SNAI) has been made to understand how such a classification can change due to a road interruption because of a bridge interruption. The contribution aims at setting the stage for the implementation of a method to determine the presence of alternative roads based on travel times adopted by the SNAI classification and, as a result, the definition of unique threshold values that justifies the variation of the exposure class and allows to determine the resilience of the whole road network.

Safeguarding Critical Infrastructures: Machine Learning in Cybersecurity

It has become essential to protect vital infrastructures from cyber threats in an age where technology permeates every aspect of our lives. This article examines how machine learning and cybersecurity interact, providing a thorough overview of how this dynamic synergy might strengthen the defence of critical systems and services. The hazards to public safety and national security from cyberattacks on vital infrastructures including electricity grids, transportation networks, and healthcare systems are significant. Traditional security methods have failed to keep up with the increasingly sophisticated cyber threats. Machine learning offers a game-changing answer because of its ability to analyse big datasets and spot anomalies in real time. The goal of this study is to strengthen the defences of key infrastructures by applying machine learning algorithms, such as CNN, LSTM, and deep reinforcement learning for anomaly algorithm. These algorithms can anticipate weaknesses and reduce possible breaches by using historical data and continuously adapting to new threats. The research also looks at issues with data privacy, algorithm transparency, and adversarial threats that arise when applying machine learning to cybersecurity. For machine learning technologies to be deployed successfully, these obstacles must be removed. Protecting vital infrastructures is essential as we approach a day where connectivity is pervasive. This study provides a road map for utilising machine learning to safeguard the foundation of our contemporary society and make sure that our vital infrastructures are robust in the face of changing cyberthreats. The secret to a safer and more secure future is the marriage of cutting-edge technology with cybersecurity knowledge.

Version control and DevOps for accelerator and experiments: Experience and outlook

GitLab has been in operation at CERN since 2012. It is a selfservice code hosting application based on Git that provides collaboration and code review features, becoming one of the key infrastructures at CERN. It is extensively utilised at CERN, with more than 17 000 active users, hosting more than 120 000 projects and triggering more than 5 000 jobs per hour. During the initial stages, a custom-made solution was deployed. However, with the exponential increase of projects, workflows, and continuous integrations, the GitLab infrastructure became hard and complex to scale and maintain. The recent migration, which involved adopting a new supported Cloud Hybrid infrastructure, has enabled CERN to align its GitLab infrastructure with industry standards and best practices. This has resulted in a significantly more robust and high-performing infrastructure, leading to notable benefits throughout the entire deployment process. This paper will address how this deployment process, on the road to success, has presented a series of challenges and pitfalls that have been faced during this complex migration process.

Repair strategies and objectives of the Autostrada dei Parchi motorway structures

The Autostrada dei Parchi, comprising the A24 and A25 motorways, is the key infrastructure of Central Italy, linking the West- and East Coasts of the Country, and is located mainly within the Region Abruzzo. It represents the only effective transverse connection, as roads and railway are obsolete and allow for very low capacity.A24+A25 contain a remarkable amount of structural works and run in a quite unfavourable environment, practically all in mountain range, with large temperature excursions, frequent rain/snow fall and high seismicity. Owned and managed by the State, they were designed and built starting in the sixties, at a time when neither professionals nor codes of practice were accounting for durability, seismic engineering was primordial and structural standards, referring to actions, zoning as well as to specifications, were rather poor.In year 2003, Strada dei Parchi SpA (SdP), a private company, took them in charge as a State Concession, through a European tender, inheriting the maintenance problems when structures already needed deep repair and strengthening, also according to new specifications on road, seismic, durability and strategic infrastructure performance.Providing general maintenance and retrofit requires important investments, released by the State on proposal of SdP, as they are far to be covered by the tolls paid by motorway users. Thus, the task is met within complex procedures and timing.Within this framework, the company fulfils the task with a proactive management of the works, based on the compliance with the standards and the search for overall sustainability. Priorities are: first, those linked to users’ safety; then to durability, according to the data of a permanent monitoring and the optimization of repair or rebuilt, before damage may affect the structural reliability. All this coordinated with the undelayable maintenance of the road platform and with the effects of “spot events”.

A Probabilistic and Distributed Validation Framework Based on Blockchain for Artificial Intelligence of Things

Artificial Intelligence of Things (AIoT) applications have advanced rapidly. However, most of them are inherently vulnerable to security threats and may be the source of spoofing attacks, and meanwhile, in AIoT systems, the transfer of real-time data from terminals and the cloud strains network bandwidth. To defend against attacks, save network forwarding resources, and relieve authentication pressure on the receiver end, it is essential to verify source identity of AIoT terminals on the forwarding path. In this paper, we propose PDIV, a probabilistic and distributed identity validation solution for AIoT applications. In the framework of PDIV, honest forwarders can verify the authenticity of the source identity of packets with a certain probability and filter spoofed packets to prevent them from spreading, reduce end-to-end network latency, and increase throughput as much as possible. Additionally, PDIV, a blockchain-based system that uses Merkle Patricia Trie (MPT) on the blockchain, makes it practical and efficient to realize distributed storage and verification of identity information. Moreover, we theorize about the trade-off between PDIV network performance and detection effectiveness, as well as how PDIV enables defenses against different attacks like spoofing and DDoS attacks. Furthermore, we implement PDIV on Network Simulator Version 3 (NS3) and evaluate its performance. The simulation results demonstrate that PDIV can prevent the spread of spoofed packets effectively and PDIV works better than currently available blockchain-based public key infrastructure (PKI) approaches in terms of network latency.

Sills and macro-roughness elements as countermeasures for bridge scour

Bridge are key infrastructures deserving attention because of their strategic role. In particular, bridges whose piers and foundations are located in water bodies are subjected to complex, localized erosion processes which may lead to undesired consequences, such as the failure of the structure. Therefore, in the last decades many researchers have analyzed the phenomenon, developing and implementing countermeasures that can mitigate the risk of a collapse. Among others, structural countermeasures like riprap, collars, and sacrificial piles have shown to be effective in reducing the maximum scour depth, under certain hydraulic conditions and geometric configurations. However, there are still some countermeasures that require further investigations. Namely, only recently, the effectiveness of transversal structures like sills and gabions have been tested. However, there are still many aspects that remain unclear, like the kinetics of the scour evolution depending on locations of the sills. In addition, macro-roughness elements may be also adopted downstream of bridge piers to protect the channel bed. This paper aims at comparing the effectiveness in controlling scour process of the last two countermeasures and provides interesting insights on the physics of the phenomenon that may be useful for practitioners. Future lines of research are also discussed.

BIBLIOMETRIC ANALYSIS OF SCIENTIFIC RESEARCH ON CURRENT PROBLEMS OF THE CRITICAL INFRASTRUCTURE DEVELOPMENT

At present, in the global world, multifaceted issues of the development of critical infrastructure in the conditions of the formation of a security environment have become especially relevant. This is due, first, to the fact that critical infrastructure facilities in the countries of the world are subject to real or potential threats created by natural disasters, ecological and man-made disasters, terrorist attacks, and military conflicts. In view of this, the purpose of this study is to determine the trends and key areas of research in the development of critical infrastructure in the context of global challenges and threats based on bibliometric analysis using the VOSviewer software. As a result of the study, it was established that the development of critical infrastructure is a process of transformational changes of priority and strategically important objects, systems, networks for the economy through the transition of key infrastructure components to a qualitatively new level of functioning due to adaptation to the variability and instability of the exogenous environment, taking into account the influence of possible threats, risks and modern challenges. In this regard, the development of critical infrastructure is connected with the processes of its modernization, restoration and reconstruction. In this regard, the article carries out a bibliometric analysis of the relationship between the terms “critical infrastructure development”, “critical infrastructure restoration”, “critical infrastructure reconstruction”, “critical infrastructure modernization”. A network visualization map of citations of articles on the development of critical infrastructure was built using the VOSviewer toolkit. Visualization of the network map of keywords based on bibliographic data made it possible to single out 4 clusters that characterize the key areas of research: identification, adaptation, digitization, disasters and natural disasters. It has been proven that the priority direction of further research should be the substantiation of the National Strategy for the Protection of Critical Infrastructure in Ukraine, taking into accounts the best world practices and the development of recommendations for improving the regulatory and legal support for the development of critical infrastructure from the standpoint of national security. Keywords: national economy, critical infrastructure, critical infrastructure objects, threat, vulnerability, danger, risk, national security, protection, sustainability, transformation, modernization, recovery, bibliometric analysis, trend analysis, cluster analysis, research clusters, international scientometric bases.

The Effect of Infrastructure Development on Poverty Alleviation in a Developing Economy: An Empirical Study from Nigeria

The study examines the effect of infrastructure development on poverty alleviation in Nigeria from 1999 to 2022, focussing on key infrastructure facilities such as transportation, energy, water, sanitation, and telecommunications. The objective of this study was to empirically ascertain the influence of these indicators in reducing poverty level in Nigeria using statistical and econometric methods such as Pearson correlation and ordinary least squares (OLS) regression. In addition, the researchers carried out a robust check on the outcomes of the study using the ARDL model, considering the principal components factor (PCA) of transport, energy, water and sanitation, and telecommunications infrastructure as a proxy for infrastructure development. The results indicate that infrastructure development has not helped in reducing poverty in Nigeria within the period of study. Specifically, the outcomes of the OLS revealed mixed results on both the direction and magnitude of the effect of infrastructure development on poverty alleviation. While the robust test validated the position that infrastructure development has not contributed to poverty reduction in Nigeria, signifying that a 0.58% increase in poverty level is associated with infrastructure development in Nigeria. The study concluded that infrastructure development in Nigeria has not effectively reduced poverty, primarily due to challenges faced by SMEs and negatively impacting living conditions across the nation. The study highlights the practical policy implications of these findings, requiring that Nigeria undertake a strategic and long-term perspective in her investment activities, similar to what has been done by successful developing countries to propel business productivity and poverty reduction.

A practical and UC-secure decentralized key management and authentication scheme based on blockchain for VNDN

In Vehicular Named Data Networking (VNDN), most of the existing key management mechanisms still rely on the hierarchical key trust model or the Public Key Infrastructure (PKI), in which the centralized certificate authority is used as a Trusted Third Party (TTP) to provide a signature for the user?s public key. Thus, the TTP becomes vulnerable to attacks and maybe there exists a singlepoint failure problem. In addition, the in-network caching in the VNDN may incur a threat to the system and make it is vulnerable to the DoS attack caused by Interest flooding aimed at the Content-Store. To tackle these security issues, we firstly propose an efficient decentralized key management solution based on blockchain for VNDN. Secondly, based on the proposed key management scheme, a lightweight mutual authentication scheme and a key agreement protocol for V2X are respectively proposed in this paper. Finally, we analyze the security attributes of our solutions in the Universally Composable (UC) framework. Our analysis results show that our novel schemes can meet the security requirements of our solutions. In addition, our experimental results show our new schemes have highly efficient, lower computation and communication costs than other related schemes.

Post-Quantum Security Overview of the Public Key Infrastructure

Recently, there has been an increasing focus on the investigation of quantum-safe solutions for a variety of applications. One of the pressing issues that needs to be made quantum secure is the TLS (Transport Layer Security) protocol. Proposals for its implementation have been discussed in several articles. The TLS protocol is based on PKI (Public Key Infrastructure). In addition, there are many other PKI applications that are used every day in both private and enterprise environments, so securing their use is essential. The methods currently developed to ensure adequate security will become obsolete with the advent of quantum computers. According to the Cloud Security Alliance, by around 2030, the performance of quantum computers will increase to the point where the risk of vulnerability of traditionally encrypted data will be very high. It is therefore important to make the right preparations in time to ensure that we can transform our solutions into quantum secure solutions by the time quantum computing becomes a real threat. In this paper, we present an analysis to this end, presenting quantum-safe solutions already in use and, in comparison, proposing new, well-performing solutions for a quantum-resistant PKI.

Teachers' Perspectives on availability of infrastructure and resources: A Quantitative Study based on Gender and Sector

A maintainable school infrastructure should provide a setting free of bias, violence, and fear, where students can feel emotionally, physically, and psychologically nurtured. Key infrastructure includes readily available and user-accessible textbooks, teaching and learning materials, print-rich environments, and other amenities and facilities, which enable students to concentrate more on their academics. The basic objective of the study was to investigate teachers’ perceptions of the school infrastructure and available resources in the 21st century. It was a descriptive study in nature using a survey research design. For data collection, a self-developed questionnaire was used comprising 30 items. Data was collected from different public and private secondary schools. Statistical Package for Social Science (SPSS) 21 was used for the analysis of data by deploying descriptive and inferential statistics e.g. a mean score, standard deviation, and t-test for comparing teachers' perceptions based on gender and sector. The result of the study revealed no significant difference based on gender and sectors which revealed teacher perception of the school infrastructure and available resources in the 21st century. All school components are in charge of maintaining the school's infrastructure and facilities.

Secure communication protocols for real-time interbank settlements

Secure communication protocols are critical for ensuring the integrity, confidentiality, and availability of real-time interbank settlements. As financial institutions increasingly rely on electronic platforms for executing high-volume and high-value transactions, the need for robust security mechanisms becomes paramount. This paper explores the key aspects of secure communication protocols in the context of real-time interbank settlements, focusing on the technologies, standards, and practices that safeguard these transactions from cyber threats. The primary objective of secure communication protocols in interbank settlements is to protect sensitive financial data from unauthorized access, tampering, and fraud. These protocols employ a combination of encryption, digital signatures, and authentication mechanisms to ensure that transactions are securely transmitted between banks and other financial entities. The implementation of advanced encryption standards (AES), Transport Layer Security (TLS), and Public Key Infrastructure (PKI) are central to maintaining the confidentiality and integrity of these transactions. In addition to encryption, secure communication protocols also incorporate real-time monitoring and anomaly detection systems to identify and respond to potential threats as they occur. These systems leverage machine learning and artificial intelligence to detect unusual patterns of activity that may indicate a security breach. Furthermore, the use of distributed ledger technologies (DLT), such as blockchain, is being explored as a means to enhance transparency and security in interbank settlements by providing an immutable record of transactions. The effectiveness of secure communication protocols in real-time interbank settlements is further strengthened by adherence to international standards, such as the ISO/IEC 27001 for information security management and the SWIFT network's Customer Security Programme (CSP). These standards provide a framework for financial institutions to assess and mitigate risks associated with interbank transactions. In conclusion, secure communication protocols are indispensable for the safe and efficient operation of real-time interbank settlements. By integrating advanced encryption, real-time threat detection, and adherence to global standards, these protocols help ensure that interbank transactions are protected from cyber threats, thereby maintaining trust and stability in the global financial system. Keywords: Secure, Communication, Protocols, Rela-Time, Interbank Settlements.

An exploration of public key infrastructure applications across diverse domains: a comparative analysis

This article delves into the vital role of Public Key Infrastructure (PKI) in securing and authenticating communications across a multitude of fields. PKI has evolved from a mere technical concept into a cornerstone of secure digital communications, playing a central role in various domains such as web security, healthcare, finance, the Internet of Things (IoT), and government services. PKI employs cryptographic techniques and digital certificates to establish trust, ensure data integrity, and enable secure communications, thus acting as the backbone of digital security. In the wake of the digital revolution, the demand for reliable and robust security solutions has skyrocketed. The diversity and scale of modern digital platforms necessitate adaptable security solutions, a challenge which PKI tackles through its flexible implementation. Despite sharing core principles, the implementation of PKI demonstrates divergences influenced by factors such as scale, complexity, resource constraints, regulatory environments, and trust models. This article offers an extensive comparison of PKI's utilization across various domains, highlighting the commonalities and divergences. It explores how PKI is tailored to meet the unique requirements and challenges of each sector and discusses the certificate lifecycle management in varying contexts. Moreover, it provides an analysis of the current state of PKI applications and challenges, offering insights into the evolving landscape of threats and technologies. Not only does the article address the current state of PKI, but it also presents a forward-looking perspective on its potential future developments. As the digital landscape continues to evolve and expand, it is crucial to anticipate the emerging challenges and devise strategies for proactive adaptation. This article thus serves as a comprehensive resource for understanding the role and impact of PKI in the contemporary digital infrastructure. Ultimately, the article seeks to underline the importance of PKI and highlight the need for continued research and development in this area. As our reliance on digital communications and transactions continues to grow, the role of PKI in safeguarding these interactions becomes increasingly significant. This comprehensive review serves as a valuable resource for researchers, practitioners, and policymakers in understanding the diverse applications of PKI and its critical role in securing the digital world.

Building a “reservoir of social resilience:” A strategy for social infrastructure regeneration in shrinking cities based on social network analysis

Northeast China is generally experiencing a shrinkage phenomenon similar to that in other old industrial regions worldwide. Large-scale growth-oriented regeneration programs by the government over the long term have led to the decline of social infrastructure in inner cities, thereby causing a structural crisis at the social level, and exacerbating the negative effects of shrinkage. This study investigated Hegang as a typical shrinking city in northeastern China. Coupling analysis was conducted based on network indexes and two categories of social resilience indexes to identify the key social infrastructure that provides residents with resilience to help cope with shrinkage. Our results demonstrate the centralizing effect of large-scale retail sites, and large green spaces and squares on social resilience. We also found that these categories of social infrastructure had effects across different areas of the city, which then provided social resilience to a wider range of residents. Our results also provide evidence for inequalities in the ability of residents to cope with shrinkage. Based on these findings, we characterize China's urban shrinkage and future development trends, and discuss the limitations of the regeneration model that has long been adopted by local governments. We suggest that local governments should consider incorporating investment in resilience to shrinkage into regeneration policies. They should also consider regenerating social infrastructure and deploying funds to a holistic network to build “reservoirs” of social resilience in shrinking cities. In addition, we highlight our methodological contributions and argue that social resilience monitoring should be integrated into China's urban physical examination framework to enhance dynamic planning and the sustainable regeneration capacity of shrinking urban local governments.

CKAA: Certificateless key‐agreement authentication scheme in digital twin telemedicine environment

AbstractDigital twin (DT) technology provides accurate and real‐time visualization data. It is increasingly used in telemedicine to enhance medical efficiency and improve the precision of remote diagnosis and treatment. In telemedicine, DT is used to collect patients' biomedical data and transmit it to cloud servers through wearable devices for simulation, enabling remote diagnosis and treatment. However, telemedicine poses security threats due to the risk of medical data leaks. The security of medical data in transit and the authentication of communication entities are two key issues in cryptography. To address these issue, we propose a certificateless key agreement authentication scheme that does not rely on traditional public key infrastructure and certificate management, reducing the storage cost of resource‐limited wearable devices and avoiding the use of bilinear pairings to lower computational costs. Our scheme includes two parts of key agreement: one between the patient and the cloud server and the other between the patient and the hospital. Through these key agreements, we can ensure the privacy and integrity of medical data during transmission. Furthermore, we prove that the security of our scheme is equivalent to the elliptic curve discrete logarithm assumption in the random oracle model. Therefore, we provide a secure and efficient certificateless key agreement authentication solution that is suitable in digital twin telemedicine environments, particularly for client devices with limited functionality.

Safety Monitoring Scheme of Gas Pipeline Network Based on Multi-homing Technology

The gas pipeline network is one of the key infrastructures for the energy supply of modern cities, and its safety is crucial to the life and development of urban residents. The traditional gas pipeline network monitoring method mainly relies on regular inspection and manual intervention, which has problems such as monitoring blind zone, slow response time and low monitoring accuracy. To address these issues, we introduce multi-homing technology into our gas network safety monitoring solution. First of all, we deploy multiple sensor nodes in key locations such as gas pipelines, valves, and connection points in the gas pipeline network, and each sensor node is equipped with multiple communication interfaces, which can be connected to different networks at the same time. We classify the collected data according to QoS traffic and assign links according to service level, and use multi-homing technology to perform multiple transmission and multiple reception, optimizing data transmission time and reliability.

Evaluating the Role of Key Infrastructure Companies in Advancing India's Smart City Initiatives: Case Studies of Larsen and Toubro Infrastructure, Reliance Infrastructure, and GMR Infrastructure Limited

Evaluating the Role of Key Infrastructure Companies in Advancing India's Smart City Initiatives: Case Studies of Larsen and Toubro Infrastructure, Reliance Infrastructure, and GMR Infrastructure Limited