Aleksandar Milenkovic

• PhD
• Professor at University of Alabama in Huntsville

The impact of total ionizing dose (TID) on commercial SRAM reveals data imprinting effects on the power-up state, starting at doses as low as 50 krad(Si). SRAM chips from smaller technology nodes appear to be less vulnerable to these imprinting effects. Additionally, we observed that the imprinting effects gradually diminish with annealing over tim...

Power-up states of SRAM memories are often used for generating Physical Unclonable Functions (PUFs) in a variety of integrated circuits. The integrity of PUFs derived from commercial SRAM memories in radiation-prone environments has been recently recognized as an important problem and it remains an open issue. We perform both experimental evaluatio...

Power-up states of SRAM chips are routinely used to derive their PUFs. Radiation effects on the integrity of SRAM PUFs have recently gained significant attention. This paper demonstrates experimentally that the data stored in SRAM during irradiation impacts the integrity of SRAM PUFs. Next, the SRAM-PUFs derived from chips manufactured using smalle...

This paper describes a new non-charge-based data storing technique in NAND flash memory called watermark that encodes read-only data in the form of physical properties of flash memory cells. Unlike traditional charge-based data storing method in flash memory, the proposed technique is resistant to total ionizing dose (TID) effects. To evaluate its...

This paper describes the results of our measurement-based study, conducted on an Intel Core i7 processor running the SPEC CPU2017 benchmark suites, that evaluates the impact of dynamic voltage frequency scaling (DVFS) on performance (P), energy efficiency (EE), and their product (PxEE). The results indicate that the default DVFS-based power managem...

The density and cost-effectiveness of flash memory chips continue to increase, driven by: (a) The continuous physical scaling of memory cells in a single layer; (b) The vertical stacking of multiple layers; and (c) Logical scaling through storing multiple bits of information in a single memory cell. The physical properties of flash memories impose...

A shift to 3-D NAND technology has resulted in flash memory blocks that include many pages, leading to “big-block” management issues in storage systems. This article experimentally explores endurance variability in 3-D NAND flash memory blocks and finds that pages in the bottom and top layers exhibit lower endurance than pages in the middle layers....

Counterfeit electronics entering the globalized supply chain are a growing problem impacting manufacturers and consumers alike. This article introduces Flash-DNA, a new technique for identifying the original chip manufacturer of nand flash memory, which will help preventing the proliferation of rebranded or cloned flash memory chips. Flash-DNA reli...

Modern processors support dynamic voltage and frequency scaling (DVFS) that can be leveraged by BIOS or OS drivers to regulate energy consumed in run-time. In this paper, we describe the results of a study that explores the effectiveness of the existing DVFS governors by measuring performance, energy efficiency, and the product of performance and e...

The SPEC CPU benchmark suites of compute-intensive benchmarks are widely used for evaluating performance of modern computer systems. Following a shift from single-core to multi-core processors, the latest suites, SPEC CPU2017, include benchmarks that are multi-threaded. This paper explores the scalability of CPU2017 benchmarks by investigating thei...

Electronic device fingerprints, unique bit vectors extracted from device's physical properties, are used to differentiate between instances of functionally identical devices. This article introduces a new technique that extracts fingerprints from unique properties of partially erased NOR flash memory cells in modern microcontrollers. NOR flash memo...

Integration of relevant hands-on cybersecurity content into laboratories supporting our required operating systems course helps to provide all computing students a baseline level of cybersecurity knowledge, even if those students never enroll in a dedicated cybersecurity course. However, these hands-on laboratories often require rebuilding of kerne...

This article demonstrates a novel technique for watermarking commercial off-the-shelf NAND flash memory chips. The technique uses repeated program-erase stressing to selectively control the physical properties of the flash cells and hence imprint watermark information into the flash media in an irreversible manner. It is accompanied by a watermark...

This article demonstrates a novel technique for generating aging-resistant, physical unclonable function (PUF) using commercial off-the-shelf NAND flash memory chips. The technique utilizes a novel "program-disturb" method using a single memory page to extract the inherent process variations unique to each chip. In addition, it employs an adaptivel...

The integration of driver assistance and autonomous driving capabilities has increased the complexity of automotive software, making the verification of software updates more challenging. The utility of simulators in software verification is limited in terms of their level of fidelity to real-world hardware and driving conditions. The use of physic...

Software debugging is one of the most challenging aspects of embedded system development due to growing hardware and software complexity, limited visibility of system components, and tightening time-to-market. To find software bugs faster, developers often rely on on-chip trace modules with large buffers to capture program execution traces with min...

In order to meet growing application demands, modern processors are constantly evolving. Today they integrate multiple processor cores, an on-chip interconnect, large shared caches, specialized hardware accelerators, and memory controllers on a single die. Compilers play a key role in bridging the gap between abstract high-level source code used by...

Computer engineers in academia and industry rely on a standardized set of benchmarks to quantitatively evaluate the performance of computer systems and research prototypes. SPEC CPU2017 is the most recent incarnation of standard benchmarks designed to stress a system's processor, memory subsystem, and compiler. This paper describes the results of m...

This paper describes the results of measurement-based studies focusing on performance and energy efficiency of SPEC CPU2017 speed and rate benchmark runs on the Intel’s Core i7-8700K processor. We measure execution time and the total energy consumed during individual benchmark runs with 1 thread/copy (1T/1C) and 6 threads/copies (6T/6C) when the pr...

An increasing reliance on cloud and distributed processing of scientific and big data in commercial, academic, and government institutions necessitate new approaches to optimize file transfers. Lossless data compression and decompression is essential in improving the overall effectiveness of file transfers between edge devices and the cloud by incr...

An increasing reliance on cloud and distributed processing of scientific and big data in commercial, academic, and government institutions necessitate new approaches to optimize file transfers. Lossless data compression and decompression is essential in improving the overall effectiveness of file transfers between edge devices and the cloud by incr...

In this paper, we propose and demonstrate a novel technique for true random number generation using commercial off-the-shelf Flash memory. Flash memory cells are known to exhibit thermal noise and random telegraph noise during sensing of their threshold voltage. In order to extract this inherent noise properties of the Flash memory bits through a s...

Mobility declines as people age, and poor mobility put older adults at risk for falls and fall-related injuries. Mobility can be improved through regular exercise and changes in medications. Professionals use standardized tests to assess mobility that rely on paper and a stopwatch. As technology improves, these same tests can be converted to smartp...

An exponential growth of data traffic that originates on mobile devices and a shift toward cloud computing necessitate finding new approaches to optimize file transfers. Whereas compression utilities can improve effective throughput of file transfers between mobile devices and the cloud, finding the best-performing utility for a given file transfer...

Objective assessment of mobility and effectiveness of interventions remains an open issue. Timed Up and Go (TUG) and 30 Second Chair Stand (30SCS) tests are routinely used in assessing mobility of subjects, but they provide a single parameter. Instrumenting subjects with wearable sensors enables a detailed mobility assessment. Specifically, we argu...

The protection of confidential information has become very important with the increase of data sharing and storage on public domains. Data confidentiality is accomplished through the use of ciphers that encrypt and decrypt the data to impede unauthorized access. Emerging heterogeneous platforms provide an ideal environment to use hardware accelerat...

The data traffic originating on mobile computing devices has been growing exponentially over the last several years. Lossless data compression can increase communication throughput, reduce latency, save energy, and increase available storage. However, compression introduces additional overhead that may exceed any gains due to transferring or storin...

Software testing and debugging of modern multicore-based embedded systems is a challenging proposition because of growing hardware and software complexity, increased integration, and tightening time-to-market. To find more bugs faster, software developers of real-time embedded systems increasingly rely on on-chip trace and debug resources, includin...

Modern smartphones integrate a growing number of inertial and environmental sensors that can enable the development of new mobile health applications. In this paper we introduce a suite of smartphone applications for assessing mobility in elderly population. The suite currently includes applications that automate and quantify the following standard...

The importance of optimizing data transfers between mobile computing devices and the cloud is increasing with an exponential growth of mobile data traffic. Lossless data compression can be essential in increasing communication through-put, reducing communication latency, achieving energy-efficient communication, and making effective use of availabl...

Mobile and embedded computing devices have become the dominant type of computing platforms. Energy-efficiency is a key requirement for these devices, underscored by growing reliance of consumers on services delivered through them and their growing complexity and sophistication. A detailed measurement-based characterization of energy consumed by app...

Mobile devices such as smartphones, tablets, and e-readers have become the dominant type of computing platforms. Energy-efficiency has become a key design and operating requirement for applications running on mobile devices. It is further underscored by a growing reliance of consumers on services delivered through mobile devices and their growing c...

The assessment of mobility and functional impairments in the elderly is important for early detection and prevention of fall conditions. Falls create serious threats to health by causing disabling fractures that reduce independence in the elderly. Moreover, they exert heavy economic burdens on society due to high treatment costs. Modern smartphones...

Virtualization technology has become ubiquitous in the computing world. With it, a number of security concerns have been amplified as users run adjacently on a single host. In order to prevent attacks from both internal and external sources, the networking of such systems must be secured. Network intrusion detection systems (NIDSs) are an important...

The health and fitness data traffic originating on mobile devices has been continually increasing, with an exponential increase in the number of personal wearable devices and mobile health monitoring applications. Lossless data compression can increase throughput, reduce latency, and achieve energy-efficient communication between personal devices a...

Continuous advances in sensors, semiconductors, wireless networks, mobile and cloud computing enable the development of integrated wearable computing systems for continuous health monitoring. These systems can be used as a part of diagnostic procedures, in the optimal maintenance of chronic conditions, in the monitoring of adherence to treatment gu...

The data traffic originating on mobile computing devices has been growing exponentially over the last several years. Lossless data compression and decompression can be essential in increasing communication throughput, reducing communication latency, achieving energy-efficient communication, and making effective use of available storage. This paper...

Software testing and debugging has become the most critical aspect of the development of modern embedded systems, mainly driven by growing software and hardware complexity, increasing integration, and tightening time-to-market deadlines. Software developers increasingly rely on on-chip trace and debug infrastructure to locate software bugs faster....

Recent technological advances in sensors, low-power integrated circuits, and wireless communications have enabled the design of low-cost, miniature, lightweight, and intelligent physiological sensor nodes. These nodes, capable of sensing, processing, and communicating one or more vital signs, can be seamlessly integrated into wireless personal or b...

Unobtrusive capturing of program execution traces in real-time is crucial for debugging many embedded systems. However, tracing even limited program segments is often cost-prohibitive, requiring wide trace ports and large on-chip trace buffers. This paper introduces a new cost-effective technique for capturing and compressing program execution trac...

Modern microprocessors integrate a growing number of components on a single chip, such as processor cores, graphics processors, on-chip interconnects, shared caches, memory controllers, and I/O interfaces. An ever-increasing complexity and the number of components present new challenges to software developers interested in finding operating points...

New health care systems that integrate wearable sensors, personal devices, and servers promise to fundamentally change the way health care services are delivered and used.

Data compression and decompression utilities can be critical in increasing communication throughput, reducing communication latencies, achieving energy-efficient communication, and making effective use of available storage. This paper experimentally evaluates several such utilities for multiple compression levels on systems that represent current m...

Posture changes initiate a dynamic physiological response that can be used as an indicator of the overall health status. We introduce an inconspicuous mobile wellness monitoring system (imWell) that continuously assesses the dynamic physiological response to posture transitions during activities of daily living. imWell utilizes a Zephyr BioHarness...

Individuals with limited ambulatory skills are at high risk for all physical inactivity-related diseases, such as coronary disease and diabetes. Increased physical activity can significantly lower risks of these diseases. However, quantifying recommendations for increased physical activity remain challenging for individuals who use wheelchairs for...

Timed-Up-and-Go (TUG) is a simple, easy to administer, and frequently used test for assessing balance and mobility in elderly and people with Parkinson's disease. An instrumented version of the test (iTUG) has been recently introduced to better quantify subject's movements during the test. The subject is typically instrumented by a dedicated device...

Capturing program and data traces during program execution unobtrusively on-the-fly is crucial in debugging and testing of cyber-physical systems. However, tracing a complete program unobtrusively is often cost-prohibitive, requiring large on-chip trace buffers and wide trace ports. This article describes a new hardware-based load data value filter...

Lossless compression and decompression are routinely used in mobile computing devices to reduce the costs of communicating and storing data. This paper presents the results of an experimental evaluation of common compression utilities on Pandaboard, a development platform similar to current commercial mobile devices. We study the compression ratio,...

Mobile computing devices such as smartphones, tablet computers, and e-readers have become the dominant personal computing platforms. Energy efficiency is a prime design requirement for mobile device manufacturers and smart application developers alike. Runtime power measurements on mobile platforms provide insights that can eventually lead to more...

Timed-Up-and-Go (TUG) is a simple, easy to administer, and frequently used test for assessing balance and mobility in elderly and people with Parkinson's disease. An instrumented version of the test (iTUG) has been recently introduced to better quantify subject's movements during the test. The subject is typically instrumented by a dedicated device...

In engineering wireless body area network platforms it is crucial to meet performance goals at minimal hardware cost and energy required. This paper describes a design flow that relies on processor customization of Tensilica's Xtensa processor cores. We introduce custom instructions to expedite wavelet processing used in an ECG R-peak detection app...

The increasing complexity of modern embedded computer systems makes software development and system verification the most critical steps in system development. To expedite verification and program debugging, chip manufacturers increasingly consider hardware infrastructure for program debugging and tracing, including logic to capture and filter trac...

Time synchronization plays an important role in wireless sensor networks, enabling correlation of diverse measurements from distributed sensor nodes, shared channel communication, and energy conservation. When designing time synchronization algorithms for wireless sensor networks, a number of parameters needs to be carefully considered, including p...

Body Area Networks integrated into mHealth systems are becoming a mature technology with unprecedented opportunities for personalized health monitoring and management. Potential applications include early detection of abnormal conditions, supervised rehabilitation, and wellness management. Such integrated mHealth systems can provide patients with i...

Capturing program and data traces during program execution unobtrusively in real-time is crucial in debugging and testing of cyber-physical systems. However, tracing a complete program unobtrusively is often cost-prohibitive, requiring large on-chip trace buffers and wide trace ports. Whereas program execution traces can be efficiently compressed i...

Unobtrusive capturing of program execution traces in real-time is crucial in debugging cyber-physical systems. However, tracing even limited program segments is often cost-prohibitive, requiring wide trace ports and large on-chip trace buffers. This paper introduces a new cost-effective technique for capturing and compressing program execution trac...

This paper introduces a new hardware mechanism for capturing and compressing program execution traces unobtrusively in real-time. The proposed mechanism is based on two structures called stream cache and last stream predictor. We explore the effectiveness of a trace module based on these structures and analyze the design space. We show that our tra...

This paper introduces a new unobtrusive and cost effective method for the capture and compression of program execution traces in real-time, which is based on a double move to front transformation. We explore its effectiveness and describe a cost effective hardware implementation. The proposed trace compressor requires only 0.12 bits per instruction...

Recent advances in sensors, low-power system-on-a-chip devices, and wireless communications, have prompted a proliferation of wireless sensor networks. These wireless sensor networks promise many new applications, such as health monitoring, traffic surveillance and navigation, habitat monitoring, warehouse inventory and asset tracking, and infrastr...

With current trends toward embedded computer systems’ ubiquitous accessibility, connectivity, diversification, and proliferation, security becomes a critical issue in embedded computer systems design and operation. Embedded computer systems are subjected to both software and physical attacks aimed at subverting system operation, extracting key secr...

Insights into branch predictor organization and operation can be used in architecture-aware compiler optimizations to improve program performance. Unfortunately, such details are rarely publicly disclosed. In this paper we introduce a set of experiment flows and corresponding microbenchmarks for reverse engineering cache-like branch target and outc...

This paper presents an implementation of a platform-independent embedded web server and its integration into a network of wireless sensor nodes. The embedded web server is designed and built as an expansion module for one of the nodes in the wireless sensor network (WSN). It allows authorized Internet users to establish two-way communication with t...

An increasing number of embedded system solutions in space, military, and consumer electronics applications rely on processor cores inside reconfigurable logic devices. Ensuring data integrity and confidentiality is of the utmost importance in many such applications. This paper describes a practical implementation of security extensions for embedde...

M-health is becoming a major technological trend for ambulatory and prolonged physiological monitoring. It has the potential to shift the paradigm of health care from reactive to proactive, from disease management to disease prevention. The widespread use of communication and information technologies facilitates the delivery of medical services at...

Addressing modes, a key component of instruction set architectures, is a mechanism machine instruction use to specify operands in general-purpose registers and memory. The text gives an overview of the most frequently used data and control-flow addressing modes and discusses their advantages and disadvantages.

Recent advances in sensors, low-power system-on- a-chip devices, and wireless communications, have prompted a proliferation of wireless sensor networks. As these networks require advanced integration, intensive onboard processing, and low power consumption, field programmable gate arrays (FPGAs) emerge as a technology that strikes an optimal balanc...

Traffic density becomes an important issue in modern cities due to sustained growth in population, higher standards of living, and increased levels of mobility. As a result, environmental pollution is on the rise, natural resource reserves are being depleted, and commute times are lengthened. These conditions are increasing the need for effective m...

Computer architecture courses are crucial core courses in computer engineering, electrical engineering, and computer science programs. Dramatic changes in technology, markets, and computer applications create a quite unique and challenging arena for computer architecture instructors and students. The goal is to provide learning environments that wi...

Software integrity and confidentiality play a central role in making embedded computer systems resilient to various malicious actions, such as software attacks; probing and tampering with buses, memory, and I/O devices; and reverse engineering. In this paper we describe an efficient hardware mechanism that protects software integrity and guarantees...

The paper presents a novel architecture for a direct digital frequency synthesizer (DDFS) based on the quasi-linear interpolation (QLIP) method. The four-segment QLIP is utilized to realize a DDFS with a spurious free dynamic range (SFDR) of 63.2dBc. The DDFS chip featuring a 5-stage pipeline is implemented in TSMC 0.13mum technology. The chip occu...

Trace-driven simulations have been widely used in computer architecture for quantitative evaluations of new ideas and design prototypes. Efficient trace compression and fast decompression are crucial for contemporary workloads, as representative benchmarks grow in size and number. This article presents Stream-Based Compression (SBC), a novel techni...

Instruction and data address traces are widely used by computer designers for quantitative evaluations of new architectures and workload characterization, as well as by software developers for program optimization, performance tuning, and debugging. Such traces are typically very large and need to be compressed to reduce the storage, process- ing,...

This paper describes a prototype system for continual health monitoring at home. The system consists of an unobtrusive wireless body area network (WBAN) and a home health server. The WBAN sensors monitor user's heart rate and locomotive activity and periodically upload time-stamped information to the home server. The home server may integrate this...

Recent technological advances in sensors, low-power integrated circuits, and wireless communications have enabled the design of low-cost, miniature, lightweight, and intelligent physiological sensor nodes. These nodes, capable of sensing, processing, and communicating one or more vital signs, can be seamlessly integrated into wireless personal or b...

Abstract, Embedded system designers face a unique set of challenges in making their systems more secure, as these systems often have stringent resource constraints or must operate in harsh or physically insecure environments. One of the security issues that have recently drawn attention is software integrity, which ensures that the programs in the...

Recent technological advances in sensors, low-power microelectronics and miniaturization, and wireless networking enabled the design and proliferation of wireless sensor networks capable of autonomously monitoring and controlling environments. One of the most promising applications of sensor networks is for human health monitoring. A number of tiny...

Recent technological advances in sensors, low-power microelectronics and miniaturization, and wireless networking enabled the design and proliferation of wireless sensor networks capable of autonomously monitoring and controlling environments. One of the most promising applications of sensor networks is for human health monitoring. A number of tiny...

Computer security becomes increasingly important with continual growth of the number of interconnected computing platforms. Moreover, as capabilities of embedded processors increase, the applications running on these systems also grow in size and complexity, and so does the number of security vulnerabilities. Attacks that impair code integrity by i...

An important problem in teaching courses in computer architecture and organization is to find a way to help students to make a cognitive leap from the blackboard description of a computer system to its utilization as a programmable device. Computer simulators developed to tackle this problem vary in scope, target architecture, user interface, and s...

Wireless sensor networks emerged as a key technology for prolonged, unsupervised monitoring in a wide spectrum of applications, from biological and environmental to civil and military. The sensor networks should operate autonomously for a long period of time under stringent resource and energy constraints. Energy conservation and power-awareness ha...

Time synchronization is essential for most network applications. It is particularly important in a wireless sensor network (WSN) as a means to correlate diverse measurements from a set of distributed sensor elements and synchronize clocks for shared channel communication protocols. Wireless sensors are typically designed with very stringent constra...

Background Recent technological advances in integrated circuits, wireless communications, and physiological sensing allow miniature, lightweight, ultra-low power, intelligent monitoring devices. A number of these devices can be integrated into a Wireless Body Area Network (WBAN), a new enabling technology for health monitoring. Methods Using off-t...

Wireless intelligent sensor networks have become a major infrastructure for deeply embedded systems. As these systems typically operate under stringent energy constraints, a careful consideration of computation and communication is crucial for extended system lifetime. To achieve extended lifetime on a limited energy budget the existing sensor plat...

With more computing platforms connected to the Internet each day, computer system security has become a critical issue. One of the major security problems is execution of malicious injected code. In this paper we propose new processor extensions that allow execution of trusted instructions only. The proposed extensions verify instruction block sign...

Recent technological advances in sensors, low-power integrated circuits, and wireless communications have enabled the design of low-cost, miniature, lightweight, intelligent physiological sensor platforms that can be seamlessly integrated into a body area network for health monitoring. Wireless body area networks (WBANs) promise unobtrusive ambulat...

Wireless body area networks (WBANs) and their supporting information infrastructures offer unprecedented opportunities to monitor state of health without constraining the activities of a wearer. These mobile point-of-care systems are now realizable due to the convergence of technologies such as low-power wireless communication standards, plug-and-p...