Accurate quantification of biological age is essential for early risk stratification and intervention of chronic diseases. Here, we present StackAge, an ensemble-based biological aging clock that integrates large-scale plasma proteomic and metabolomic profiles from 30 376 participants in the UK Biobank. StackAge demonstrated high accuracy in age prediction (Pearson r ≈ 0.93 with chronological age) and substantially enhanced risk prediction for 12 chronic diseases, achieving AUCs exceeding 0.90 for type 2 diabetes, Alzheimer's disease, and chronic kidney disease. Notably, the incorporation of estimated aging rates consistently improved disease prediction beyond conventional omics and demographic features. Feature interpretation and pathway enrichment analyses revealed that aging-associated biomarkers were enriched in inflammation, metabolic stress, and extracellular matrix remodeling pathways. Mediation analysis further indicated that modifiable lifestyle factors may accelerate biological aging, thereby increasing susceptibility to cardiovascular, neurological, immune, and musculoskeletal disorders. Together, these findings establish a robust multi-omics framework for quantifying individual aging trajectories and highlight biological age as a clinically actionable indicator for precision prevention and health management of age-related diseases.

Summary Software complexity is the very essence of computer programming. As the complexity increases, the potential risks and defects of software systems will increase. This makes the software correctness analysis and the software quality improvement more difficult. In this paper, we present a quantitative metric to describe the complexity of a hierarchical software and a Complexity‐oriented Software Architecture Refactoring (CoSSR) approach to reduce the complexity. The main idea is to identify and then reassemble subcomponents into one hierarchical component, which achieves minimum complexity in terms of the solution algorithm. Moreover, our algorithm can be improved by introducing partition constraint, heuristic search strategy, and spectral clustering. We implement the proposed method as an automated refactoring tool and demonstrate our algorithm through a case study of battery management system (BMS). The results show that our approach is more efficient and effective to reduce the complexity of hierarchical software system.

Nowadays, the utilization of online auction platforms is becoming increasingly prevalent.Online auction provides a common and practical way for global buyers to compete fairly.Nevertheless, the anonymous environment may bring collusion among entities with effects on results.Compared with traditional mechanisms which rely on third-party platforms, the data auction based on smart contract can create a decentralized environment to avoid the occurrence of collusion.Meanwhile, there exists few research on the verification of its reliability and safety which is worth investigating from the perspective of formal methods.In this paper, we apply Process Algebra CSP in modeling the data auction communicating system among five key entities.In addition, we use Process Analysis Toolkit (PAT) to realize the mechanism and verify five crucial properties, including deadlock freedom, data reachability, data correctness, anti-collusion capability and data security.The verification results indicate that the architecture of data auction based on smart contract can satisfy all the above requirements.Especially, the design of asymmetric encryption for the fundamental information ensures the non-occurrence of collusion in the auction.Additionally, the digital signature generated by private key attached to the message guarantees the safety of the interaction.

As IoT in a multi-server environment increases resources’ utilization, more and more problems of IoT authentication and key agreement are being revealed. The Authentication and Key Agreement (AKA) protocol plays an important role in solving these problems. Many AKA protocols have been proposed, and some of them support their own verifications. However, a unifying verification framework for multi-server IoT is lacking. In this article, we propose a formal verification framework of AKA protocols for multi-server IoT (FVF-AKA). It supports the construction of CSP models for the AKA protocol, the implementation of the CSP models in PAT with C#, and the verification of formal models. With the help of C#, many complex functions in the AKA protocol can be implemented. We also design an algorithm to support automatic conversion from the CSP model to the PAT model. FVF-AKA can verify four fundamental properties (deadlock freedom, entity legitimacy, timeout delay, and session key consistency). It also supports the verification of security properties for the AKA protocol suffering from four different attacks (relay attacks, denial of service attacks, server spoofing attacks, and session key attacks). Our approach can be applied to most AKA protocols for multi-server IoT generally. By applying FVF-AKA to two AKA protocols, we can verify whether they satisfy the fundamental properties and analyze their security properties in vulnerable environments. Our work would help to analyze the AKA protocol for multi-server IoT and provide the foundation for the analysis of enhancing its security and robustness.

Abstract Named Data Networking (NDN) is a new promising architecture of information‐centric networking, which supports multicast of data and adopts the publish/subscribe model in the network. The features of NDN, including name‐based data and in‐network caching, make it a promising Internet architecture for cyber‐physical systems (CPSs). Named‐Data Link State Routing (NLSR) protocol is the routing protocol for NDN, which is designed to disseminate link state advertisements (LSAs) to both build a network topology and distribute all the name prefixes to every node in the network. In this paper, we make the very first attempt to formally model and verify some fundamental properties of the NLSR protocol using model checker UPPAAL. We validate the NLSR protocol modeled into timed automata with simulator in UPPAAL. We verify our model with four fundamental properties (termination, reachability of Sync Interest , reachability of Sync Data , and digest synchronization). The first synchronization problem is found in a scenario with two nodes topology. We give the improved model that owns a valid result in digest synchronization verification. To capture more problems, we make the model to support the simulation of temporary network crash. The second synchronization problem is also exposed in two comparative scenarios. We also propose a mechanism implemented in our model, which has a valid result in digest synchronization verification. We hope that our study and preliminary results would help enhancing the adaptability and robustness of NLSR protocol.

Abstract As a crucial component of intelligent transportation system, Internet of Vehicles (IoV) plays an important role in the smart and intelligent cities. However, current Internet architectures cannot guarantee efficient data delivery and adequate data security for IoV. Therefore, Named Data Networking (NDN), a leading architecture of Information‐Centric Networking (ICN), is introduced into IoV. Although problems about data distribution can be resolved effectively, the combination of NDN and IoV causes some new security issues. In this paper, we apply Communicating Sequential Processes (CSP) to formalize NDN‐based IoV. We mainly focus on its data access mechanism and model this mechanism in detail. By feeding the formalized model into the model checker Process Analysis Toolkit (PAT), we verify four vital properties, namely, deadlock freedom, data reliability, PIT deletion faking, and CS caching pollution. According to verification results, the model cannot ensure the security of data with the appearance of intruders. To solve these problems, we construct a blockchain‐based mechanism by creating a blockchain‐based distribution trusted platform on top of NDN‐based IoV. Through the analysis of the improved model, the blockchain‐based mechanism can truly guarantee the security of NDN‐based IoV.

Mobile Edge Computing (MEC), as an emerging technology, is proposed to solve the time delay problem in 5G era, especially in the field of autonomous driving. The core idea of MEC is to offload the task to the nearest device/server for computation, i.e., sinking the computation, so as to reduce the delay and congestion. Actually, there are lots of researches on MEC offloading strategy, but there is little research on the computation of its offloading characteristics. Therefore, in this paper, we first propose a secure hierarchical calculus SC4MEC to describe the features of MEC. We also give the syntax and operational semantics of this calculus from the process and network levels, and simulate the calculus in Maude. Meanwhile, local ecology is applied to the communication channel to further reduce the authentication delay of the device with the same identity and ensure the security of the transmission data. We also propose to extend the communication radius of MEC server or cloud server by rule Enlarge, in order to ensure the mobile devices's connectivity while the consumption of resources is minimized. Finally, we employ SC4MEC calculus to a small example about device to device communication with automated implementation.

With the popularization and development of 5G, it is vital to guarantee the security of the whole data while transmitting them at high speed. Data Distribution Service (DDS), as the core technology of network data communication, is one of the most significant protocols. The Real Time Publish Subscribe (RTPS) protocol is part of DDS, which emphasizes data publishing and receiving.In this paper, we focus on the Behavior module of the RTPS protocol, where the reliable modes are always to ensure the reliability of data. Thus, we adopt CSP to model eight core components and add corresponding intruders to attack the model in order to verify and detect the potential risks of the design. Specifically, we also improve our model by utilizing digital signature and digital certificate. Five properties abstracted from the specification have been verified through the model checker PAT. The result shows that once adding the digital signature and digital certificate together, there is no situation that publisher and subscriber are unauthorized; in addition, due to multiple encryption, data cannot be faked or intercepted. However, the history-cache still can be faked for it has no identity authentication. That is to say, to be highly trustworthy, developers need to ensure mutual authentication between modules as much as possible. Consequently, we hope this method makes sense for researches on security of data distribution protocol and gives a meaningful guide for DDS middleware development.

The combination of D2D (Device to Device) communication and MEC (Mobile Edge Computing) architecture is adopted to reduce the communication delay in 5G. With the extensive use of HPS (high performance switch) as the main medium of data distribution in the device layer, the holistic power consumption and delay can be guaranteed stably, mainly because HPS has the mechanism of Master-Slave scheme to ensure the robustness. However, as far as we know, there are fewer studies to verify the safety validation of the design using formal methods. Hence, we study it through timed automata and model checking. This paper integrates HPS into D2D communication design in MEC, selects the Master-Slave synchronization and switchover scheme in HPS as the research object, describes the scheme based on timed automata, and then verifies seven fundamental but essential properties through the model checker UPPAAL. Through verification, comparison and analysis of possible scenarios in our constructed model, it can be concluded that the design of the HPS in MEC can conform to its required specification. Further, it can not only enhance the safety validation of the combination of D2D communication and MEC architecture, but also provide a guide for the newest subsequent high safety primary-backup design in industry.

As a leading architecture of Information-Centric Networking (ICN), Named Data Networking (NDN) plays an important role in the future network construction. NDN retrieves and identifies a data packet according to the packet's name instead of its IP address. Conventional protocols of TCP/IP Internet are unsuitable for NDN. Therefore, Named-data Link State Routing protocol (NLSR) is proposed as an intra-domain routing protocol for NDN. Although NLSR applies a five-layer trust model to guarantee its data security, there are still a lot of security issues in its data access mechanism, such as the fake and leakage of data. In this paper, we apply Communicating Sequential Processes (CSP) to formalize this mechanism. Using Process Analysis Toolkit (PAT), we verify four properties, including deadlock freedom, data availability, data security and data decryption. According to the verification results, the trust model cannot protect the data from fake and leakage once intruders appear. We adopt a method similar to digital signature in the first improved model. However, the process of obtaining keys still needs to be executed multiple times during the verification of a data packet. To further accelerate the key fetching and verification process, all the keys, needed to validate a data packet, are packaged in a special packet of the second improvement.

Cloud computing is an emerging computing paradigm in IT industries.The wide adoption of cloud computing is raising concerns about management of data in the cloud.Access control and security are two critical issues of cloud computing.Time efficient secure access control (TESAC) model is a new data access control scheme which can minimise many significant problems.This scheme has better performance than other existing models in a cloud computing environment.TESAC is attracting more and more attentions from industries.Hence, the reliability of TESAC becomes extremely important.In this paper, we apply Communication Sequential Processes (CSP) to model TESAC, as well as their security properties.We mainly focus on its data access mechanism part and formalize it in detail.Moreover, using the model checker Process Analysis Toolkit (PAT), we have verified that the TESAC model cannot assure the security of data with malicious users.For the purpose of solving this problem we introduce a new method similar to digital signature.Our study can improve the security and robustness of the TESAC model.

The Real Time Publish Subscribe protocol (RTPS), as a Data Distribution Service (DDS) protocol for computer systems, is composed of several modules.We focus on RTPS StatefulWriter Module which has two patterns, reliable pattern and best-effort pattern.As the main module of sending and receiving messages, its security and reliability are of great concern.The formal method can analyze whether it is a highly credible model from the mathematical point of view.Our research pays attention to the reliable pattern.Thus it is of great importance to model and verify whether the pattern is reliable through formal methods.In this paper, we model seven components of the module using Communicating Sequential Processes (CSP).By feeding the models into the model checker Process Analysis Toolkit (PAT), we verify four properties, divergence free, acknowledgement mechanism, data consistency and sequentiality.Consequently, it can be apparently concluded that the pattern of this module is reliable, which totally caters for its specification.

Cloud computing is an emerging computing paradigm in IT industries. The wide adoption of cloud computing is raising concerns about management of data in the cloud. Access control and data security are two critical issues of cloud computing. Time-efficient secure access control (TESAC) model is a new data access control scheme which can minimize many significant problems. This scheme has better performance than other existing models in a cloud computing environment. TESAC is attracting more and more attentions from industries. Hence, the reliability of TESAC becomes extremely important. In this paper, we apply Communication Sequential Processes (CSP) to model TESAC, as well as their security properties. We mainly focus on its data access mechanism part and formalize it in detail. Moreover, using the model checker Process Analysis Toolkit (PAT), we have verified that the TESAC model cannot assure the security of data with malicious users. For the purpose of solving this problem, we introduce a new method similar to digital signature. Our study can improve the security and robustness of the TESAC model.

Named Data Networking (NDN) is a new promising architecture of information-centric networking.For its caching property, traditional mechanisms of access control can no longer work.Hamdane et al. propose a new access control solution for both closed and open environments.In this paper, we make the very first attempt to formally analyze this access control solution.Inspired by the basic BAN logic which is often used to describe protocols by logical formulas, we present our BAN-like logic by adding some new notions to make it suitable for the access control solution.Using the BAN-like logic, the procedures of the access control solution is idealized in the form of the beliefs of principals.Then the idealized procedures are analyzed under several security goals with a set of logical postulates.Several unsatisfied goals may lead the access control solution to be vulnerable to intruders.We give the modification in the idealized procedures to archive more goals.We also present the related modification in the implementation of the access control solution.Our study helps to improve security and protect against various attacks for the access control solution.

Software Defined Network (SDN) is an emerging architecture of computer networking.The most important feature of SDN is that it separates the control plane from the data plane.OpenFlow is considered as the first and currently most popular standard southbound interface of SDN.It is a communication protocol which enables the SDN controller to directly interact with the forwarding plane.The widespread use makes the reliability of OpenFlow important.The OpenFlow bundle mechanism is a new mechanism proposed by OpenFlow protocol to guarantee the completeness and consistency of the messages transmitted between SDN switches and controllers during the communication process.Due to the requirement of reliability and security of OpenFlow, we think that it is of great significance to formally analyze and verify the safety-relevant properties of the mechanism.In this paper, we apply Communication Sequential Processes (CSP) and the model checker Process Analysis ToolKit (PAT) to model and verify the OpenFlow bundle mechanism.Our formalization and verification show that the mechanism can satisfy four properties: deadlock freeness, parallelism, atomicity and order property, from which we can conclude that the mechanism offers a better way to guarantee the completeness and consistency.

Named Data Networking (NDN) is a new promising architecture of information-centric networking, which supports multicast of data and adopts the publish/subscribe model in the network. NDN could not reuse the existing routing protocols designed for the IP architecture due to their fundamental difference of design. As a result, the Named-data Link State Routing (NLSR) protocol has been proposed for NDN. At the heart of the NLSR protocol is to disseminate Link State Advertisements (LSAs) to both build a network topology and distribute all the name prefixes to every node in the network. Each router stores the latest version of the LSAs in a Link State Database (LSDB). In this paper, we make the very first attempt to formally model and verify a few fundamental properties of the NLSR protocol using UPPAAL, a model checker for modeling and verifying real-time systems as networks of timed-automata. We validate our model by running the simulator in UPPAAL and verify crucial properties of the protocol under simple yet non-trivial test configurations differing in network topologies and message exchanging scenarios. We capture two situations that may risk synchronization failures and discuss some countermeasures. We also testify the proposal by verifying the revised model with addressing the design issues. We hope that our study and preliminary results would help enhancing the adaptability and robustness of NLSR protocol.

Software-Defined Networking (SDN) is an emerging architecture of computer networking. OpenFlow is considered as the first and currently most popular standard southbound interface of SDN. It is a communication protocol which enables the SDN controller to directly interact with the forwarding plane, which makes the network more flexible and programmable. The promising and widespread use makes the reliability of OpenFlow important. The OpenFlow bundle mechanism is a new mechanism proposed by OpenFlow protocol to guarantee the completeness and consistency of the messages transmitted between SDN devices like switches and controllers. In this paper, we use Communication Sequential Processes (CSP) to formally model the OpenFlow bundle mechanism. By adopting the models into the model checker Process Analysis Toolkit (PAT), we verify the relevant properties of the mechanism, including deadlock freeness, parallelism, atomicity, order property and schedulability. Our formalization and verification show that the mechanism can satisfy these properties, from which we can conclude that the mechanism offers a better way to guarantee the completeness and consistency.

Abstract The POSIX threads (Pthreads) library is a thread API for C/C++ to control parallel threads and spawn concurrent process flows. Programming in Pthreads usually suffers from undesirable deadlock, data race, and race condition problems due to the potential nondeterministic execution behaviors between parallel threads. Dthreads, as another multithreading model that re‐implements Pthreads, was proposed by Liu et al for efficient deterministic multithreading. They found out that, under specific test cases, Dthreads can effectively prevent data races. However, no comparison test has been made with Pthreads. To perform a formal comparison between Pthreads and Dthreads over deadlocks, data races, and race conditions, in this paper, we adopt CSP (communicating sequential processes) as a formal model for specifying part of API functions in Pthreads and Dthreads and illustrate the model construction using 4 classical example programs. By feeding the models into the model checker PAT (process analysis toolkit), we have verified that deadlocks and data races exist in Pthreads, but do not exist in Dthreads, for the considered programs. We have also found that neither of them can prevent race conditions. Our comparative modelling and verification of Pthreads and Dthreads show that though Dthreads cannot prevent all the deadlock situations, shown by verification results of another 2 example programs, Dthreads is better than Pthreads on eliminating data races and preventing deadlocks. Considering limited scalability of Dthreads, we have introduced a new programming model to support coarse granularity in bank transfer. Our modelling is also extended by covering the synchronization operations in Liu et al work.

The security protocol is proposed as a security solution for end-to-end communication between smart grid applications in the EU FP7 project C-DAX. Since the importance and widespread use of the security protocol, it is of great significance to formally analyze and verify relevant security properties of this security protocol. In this paper, we apply Communicating Sequential Processes (CSP) to model the security protocol. Further, we use the model checker Process Analysis Toolkit (PAT) to automatically simulate the developed model, and verify whether the model caters for the specification and relevant secure properties, e.g. reachability of the fake goal. Our modeling and verification show that a risk may exist in the security protocol.