With the rapid advancement in information technology, embedded systems have become integral to a wide range of critical applications. These systems often require continuous operation and cannot tolerate the downtime associated with traditional software updates, which typically necessitate a system reboot. To address this challenge, this paper proposes a novel hotpatching technique called Flexible Linked EXecution (FLEX) designed specifically for real-time embedded environments. FLEX enables seamless, dynamic firmware updates by redirecting all function calls and global variable accesses through a compile time generated Control Flow Table (CFT). In contrast to existing hotpatching approaches that depend on specialized hardware or impose strict limits on the number of patches and their size, FLEX is entirely hardware independent and supports scalable patching capacity bounded only by available flash memory and RAM. FLEX offers several unique features, including a relaxed consistency state synchronization mechanism to allow for gradual migration of program state, resolving all symbols at compile time into CFT indirections, applying updates via a double-buffered pointer swap to a new CFT, and a XIP compatible process that guarantees only a short, bounded pause time regardless of patch complexity. Experimental results show that FLEX maintains system stability and performance with an average execution overhead of about 11% and a predictable increase in flash memory usage of roughly 17%. These findings suggest that FLEX offers a robust and flexible solution for dynamically updating the software of embedded systems to ensure high availability and security without sacrificing performance.

Embedded systems rely on real-time operating systems (RTOS) for safety-critical applications, but the absence of fine-grained memory protection poses serious security risks. Existing protection mechanisms either require specialized hardware or rely on static configurations that fail to adapt to dynamic task behavior. This paper introduces Runtime Enforcement of Memory Access Protection (REMAP), which is a novel framework that combines LLVM-based static analysis with runtime Memory Protection Unit (MPU) reconfiguration to achieve fine-grained, dynamic compartmentalization for RTOS environments. REMAP constructs task-specific Access Control Table (ACT) at compile time and enforces them at runtime through on-demand MPU updates triggered by memory access violations. This lazy mapping strategy allows REMAP to support hundreds of compartments per task despite the limitation on the number of hardware MPU slots. Our prototype on ARMv8-M (Cortex-M33) demonstrates that REMAP enforces memory access control down to the function and variable level, protects shared buffers for secure Inter Process Communication (IPC), and prevents error propagation across tasks. Evaluation using the BEEBS benchmark suite shows that compartment merging significantly reduces fault frequency, yielding overheads under 5% across all benchmarks. Therefore, REMAP achieves precise, adaptive memory protection suitable for commercial RTOS deployments without compromising real-time performance.

Counterfactual quantum communication enables communication between remote parties without transmitting any information-carrying particle. In this paper, we propose four protocols for secure quantum communication networks utilizing such communication. The first protocol, counterfactual quantum secure direct communication (CQSDC), enables a sender to securely and counterfactually communicate a secret message. The second protocol, counterfactual quantum secure dialogue (CQSD), allows legitimate parties to transmit secret messages in each direction simultaneously, securely and counterfactually. The third protocol, counterfactual controlled quantum teleportation (CCQT), facilitates a sender to counterfactually teleport a quantum state to a receiver under the supervision of a controller. Finally, the fourth protocol, counterfactual quantum private comparison (CQPC), capacitates a third party to compare the private states of the end parties without the actual knowledge of the counterfactually transmitted states. We devise the CQSDC and CQSD protocols by exploiting the counterfactual Swap, dual chained quantum Zeno (CQZ), and distributed controlled NOT gates. For CCQT and CQPC protocols, we utilize CQZ gates with a horizontally polarized photon input. We show that the security of CQSDC and CQSD relies on counterfactual entanglement swapping, while that of CCQT and CQPC depends on establishing secure counterfactual communication channels and security validation with decoy particles, respectively.

The proliferation of Internet of Things (IoT) devices comes with many challenges among which security is one of the most serious issues. In order to address the security issue for low-end IoT devices, ARM recently proposed the platform security architecture (PSA), which provides execution isolation to safely manage and protect the computing resources of low-end IoT devices. However, developers implementing IoT services for PSA-based IoT devices need to follow complex development procedures and understand the PSA hardware, which dramatically increases the development time and cost of PSA-based IoT devices. This article analyzes vulnerabilities that may arise from general-purpose low-end IoT devices to derive the security requirements and essential security services for PSA-based IoT devices, and proposes a secure platform model based on the analysis results. The proposed secure platform model consists of System Security Services and Application Security Services based on the basic PSA model and essential trusted subsystems, and it is designed to be flexible and applicable to various types of PSA-based IoT devices. In addition, it provides secure platform services APIs to enable easy and fast development of IoT services. To evaluate the proposed secure platform model, two proof-of-concept implementations are provided by using both the basic PSA model with secure element (SE) and a reference device for ARM’s PSA. Finally, a case study shows that the development of IoT services can be done easily and quickly using the proposed security platform model.

Recent technological advances in wireless sensor networking have opened up new opportunities in healthcare systems. Future medical systems are expected to benefit the most in such areas as in-home assistance, smart nursing homes, and clinical trial. However the network system including body sensor networks and environmental sensor networks are normally comprised of energy constrained nodes. Furthermore, communication interference between multi mode nodes in such a dynamic system is also a challenge. This limitation has led to the crucial need for energy and mobility aware protocols to produce an efficient network. In this paper, we propose an energy and mobility aware multipath routing scheme for sensor networks in a smart homecare application. The remaining battery capacity, distance to the gateway, mobility and queue size of candidate sensor nodes in the local communication range are taken into consideration for next hop relay node selection, and Analytical Hierarchy Process (AHP) is applied for decision making. Simulation results show that this scheme can extend the network lifetime and reduce the packet loss rate and link failure rate since the mobility and buffer capacity is considered.

Multimedia services over a CDMA2000 broadcast network face a challenge from the unreliable and error-prone nature of the radio channel. Reed–Solomon (RS) coding, integrated with the MAC protocol, is used to cope with this problem. However, performance analysis of RS coding under varying channel conditions shows that it is not always effective, especially for slow-moving nodes which experience relatively long error bursts. Therefore a more efficient scheme is proposed that uses a RS code with reduced parity overhead, and freeing bandwidth can be used flexibly for retransmission. The packets to be retransmitted are prioritised by a utility function derived from the map of the error control block at each mobile node and the number of mobile nodes that require the lost packet. Simulation results show that the gain of retransmission exceeds the loss incurred by reducing the parity, leading to an improvement in the playback quality of MPEG-4 video streams. As a result, service area for high-quality multimedia can be expanded.

In this paper, we propose an approach to collaboratively track motion of a moving target in a wide area utilizing camera-equipped visual sensor networks, which are expected to play an essential role in a variety of applications such as surveillance and monitoring. A genetic fitting method for efficient contour extraction is used as inter-scene approach to detect and track the target. We also considered the existence of faulty sensors in the network which deteriorate the difficulty of target tracking problem, and proposed a robust sensor collaboration method. The experimental results have shown that the proposed target tracking approach produces very successful target tracking compared with the existing method especially in case that the target is adjacent to neighboring objects of background

cdma2000 1/spl times/EV-DO, one of the prominent 3G mobile communication systems, provides broadcast and multicast services (BCMCS) to meet increasing demand for multimedia data services. Currently, 1/spl times/EV-DO schedules broadcast streams using a slot-based static algorithm, which fails to support dynamic environments where broadcast content is added or removed on-line. We propose a dynamic packet-scheduling algorithm that works with a retransmission scheme for the BCMCS scheduler. Integrated with earliest deadline first (EDF) real-time scheduling, the proposed algorithm not only adapts to dynamic contexts efficiently but also satisfies the real-time requirements of broadcast streams. Furthermore, by exploiting the fine granular scalable (FGS) characteristics of the MPEG-4 part 2 standard, our scheme can avoid abrupt degradation of playback quality by protecting the most important data. Extensive simulations have quantitatively validated the efficiency of our approach.

Video broadcast services have become increasingly popular on packet-based wireless networks, such as 1xEV-DO and HSDPA which support high data rate. In this paper we propose a resource allocation algorithm for scalable video broadcast over such wireless networks. Our algorithm allocates time slots among the video layers of a scalable video and applies adaptive modulation and coding (AMC) to each video layer to maximize the sum of utilities for heterogeneous users with varying QoS requirements. It also considers competing video sessions and allocates time slots among them according to user preferences. Additionally, its polynomial time-complexity allows for online resource allocation that is necessary for real-time video services. Simulation experiments show that our algorithm outperforms a single-layer video broadcast with fixed modulation and coding (FMC), used in broadcast and multicast services (BCMCS) in the CDMA2000 system, and produce a near-optimal allocation.

High-performance memory buses consume large energy as they include termination networks, BiCMOS and/or open-drain output. This paper introduces power reduction techniques for memory systems deliberating on burst-mode transfers over the high-speed bus specifications such as Low Voltage BiCMOS (LVT), Gunning Transfer Logic (GTL+) and Stub Series Termination Logic (SSTL 2) which are widely used. The reduction techniques take both the static and the dynamic power consumption into account because most high-performance bus drivers and end-termination networks dissipate significant static power as well. Extensive performance analysis is conducted through mathematical analysis and trace datadriven simulations. We had reduction of 14 % with random data and up to 67.5 % with trace data. 1.