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Open Access Issue
Bluetooth Low Energy Device Identification Based on Link Layer Broadcast Packet Fingerprinting
Tsinghua Science and Technology 2023, 28 (5): 862-872
Published: 19 May 2023
Downloads:81

With the rapid development of the Internet of Things (IoT), wireless technology has become an indispensable part of modern computing platforms and embedded systems. Wireless device fingerprint identification is deemed as a promising solution towards enhancing the security of device access authentication and communication process in the IoT scenario. However, the extraction of features from the network layer and its upper layers often confront restrictions from specific devices: the association with a certain wireless network and the access to the plaintext of the payload. Meanwhile, Bluetooth Low Energy (BLE) packets have been encrypted above the link layer, which makes those features difficult to extract. To tackle these problems, we introduce a novel method to identify BLE devices based on the fingerprint features in the data link layer. Initially, the BLE packets are collected through a receiver based on software-defined radio technology. Then, fields that reflect device differences in BLE broadcast packets are extracted through traffic analysis. Finally, a MultiLayer Perceptron (MLP) model is employed to recognize the category of BLE devices. An experimental result on a dataset with 15 types of BLE devices shows that the identification accuracy of the proposed method can reach 99.8%, which accomplishes better performance over previous work.

Open Access Issue
Thermal-Aware on-Device Inference Using Single-Layer Parallelization with Heterogeneous Processors
Tsinghua Science and Technology 2023, 28 (1): 82-92
Published: 21 July 2022
Downloads:97

Numerous neural network (NN) applications are now being deployed to mobile devices. These applications usually have large amounts of calculation and data while requiring low inference latency, which poses challenges to the computing ability of mobile devices. Moreover, devices’ life and performance depend on temperature. Hence, in many scenarios, such as industrial production and automotive systems, where the environmental temperatures are usually high, it is important to control devices’ temperatures to maintain steady operations. In this paper, we propose a thermal-aware channel-wise heterogeneous NN inference algorithm. It contains two parts, the thermal-aware dynamic frequency (TADF) algorithm and the heterogeneous-processor single-layer workload distribution (HSWD) algorithm. Depending on a mobile device’s architecture characteristics and environmental temperature, TADF can adjust the appropriate running speed of the central processing unit and graphics processing unit, and then the workload of each layer in the NN model is distributed by HSWD in line with each processor’s running speed and the characteristics of the layers as well as heterogeneous processors. The experimental results, where representative NNs and mobile devices were used, show that the proposed method can considerably improve the speed of the on-device inference by 21%–43% over the traditional inference method.

Open Access Issue
A Dynamic and Deadline-Oriented Road Pricing Mechanism for Urban Traffic Management
Tsinghua Science and Technology 2022, 27 (1): 91-102
Published: 17 August 2021
Downloads:71

Road pricing is an urban traffic management mechanism to reduce traffic congestion. Currently, most of the road pricing systems based on predefined charging tolls fail to consider the dynamics of urban traffic flows and travelers’ demands on the arrival time. In this paper, we propose a method to dynamically adjust online road toll based on traffic conditions and travelers’ demands to resolve the above-mentioned problems. The method, based on deep reinforcement learning, automatically allocates the optimal toll for each road during peak hours and guides vehicles to roads with lower toll charges. Moreover, it further considers travelers’ demands to ensure that more vehicles arrive at their destinations before their estimated arrival time. Our method can increase the traffic volume effectively, as compared to the existing static mechanisms.

Open Access Issue
Efficient Location-Aware Data Placement for Data-Intensive Applications in Geo-distributed Scientific Data Centers
Tsinghua Science and Technology 2016, 21 (5): 471-481
Published: 18 October 2016
Downloads:31

Recent developments in cloud computing and big data have spurred the emergence of data-intensive applications for which massive scientific datasets are stored in globally distributed scientific data centers that have a high frequency of data access by scientists worldwide. Multiple associated data items distributed in different scientific data centers may be requested for one data processing task, and data placement decisions must respect the storage capacity limits of the scientific data centers. Therefore, the optimization of data access cost in the placement of data items in globally distributed scientific data centers has become an increasingly important goal. Existing data placement approaches for geo-distributed data items are insufficient because they either cannot cope with the cost incurred by the associated data access, or they overlook storage capacity limitations, which are a very practical constraint of scientific data centers. In this paper, inspired by applications in the field of high energy physics, we propose an integer-programming-based data placement model that addresses the above challenges as a Non-deterministic Polynomial-time (NP)-hard problem. In addition we use a Lagrangian relaxation based heuristics algorithm to obtain ideal data placement solutions. Our simulation results demonstrate that our algorithm is effective and significantly reduces overall data access cost.

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