The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

The spatial features of emitted wireless signals are the basis of location distinction and determination for wireless indoor localization. Available in mainstream wireless signal measurements, the Received Signal Strength Indicator (RSSI) has been adopted in vast indoor localization systems. However, it suffers from dramatic performance degradation in complex situations due to multipath fading and temporal dynamics. Break-through techniques resort to finer-grained wireless channel measurement than RSSI. Different from RSSI, the PHY layer power feature, channel response, is able to discriminate multipath characteristics, and thus holds the potential for the convergence of accurate and pervasive indoor localization. Channel State Information (CSI, reflecting channel response in 802.11 a/g/n) has attracted many research efforts and some pioneer works have demonstrated submeter or even centimeter-level accuracy. In this article, we survey this new trend of channel response in localization. The differences between CSI and RSSI are highlighted with respect to network layering, time resolution, frequency resolution, stability, and accessibility. Furthermore, we investigate a large body of recent works and classify them overall into three categories according to how to use CSI. For each category, we emphasize the basic principles and address future directions of research in this new and largely open area.

From RSSI to CSI: Indoor Localization via Channel Response, A survey on indoor localization using PHY-layer information

This paper presents a state-of-the-art survey of smartphone (SP)-based solutions for fall detection and prevention. Falls are considered as major health hazards for both the elderly and people with neurodegenerative diseases. To mitigate the adverse consequences of falling, a great deal of research has been conducted, mainly focused on two different approaches, namely, fall detection and fall prevention. Required hardware for both fall detection and prevention are also available in SPs. Consequently, researchers' interest in finding SP-based solutions has increased dramatically over recent years. To the best of our knowledge, there has been no published review on SP-based fall detection and prevention. Thus in this paper, we present the taxonomy for SP-based fall detection and prevention solutions and systematic comparisons of existing studies. We have also identified three challenges and three open issues for future research, after reviewing the existing articles. Our time series analysis demonstrates a trend towards the integration of external sensing units with SPs for improvement in usability of the systems.

https://www.mdpi.com/1424-8220/14/4/7181/pdf

Smartphone-based solutions for fall detection and prevention: challenges and open issues

본 논문에서는 Dr Gerald J. Holzmann이 제시하였던 커널 스케줄링 방식을 프로세스 알제브라 ACSR-VP를 이용해서 있음을 보인다. 본 오류는 SPIN을 통하여 역시 확인하였다. 이것을 다시 모델링하여 오류를 수정하였고 ACSR-VP와 SPIN으로 오류가 수정되었음을 확인하였다.

Holzmann의 ˝The Model Checker SPIN˝에 대하여

Video encryption has been heavily researched in the recent years. This survey summarizes the latest research results on video encryption with a special focus on applicability and on the most widely-deployed video format H.264 including its scalable extension SVC. The survey intends to give researchers and practitioners an analytic and critical overview of the state-of-the-art of video encryption narrowed down to its joint application with the H.264 standard suite and associated protocols (packaging/streaming) and processes (transcoding/watermarking).

/pdf/a-survey-of-h-264-avc-svc-encryption-1r171okq0l.pdf

A Survey of H.264 AVC/SVC Encryption

Current FDT compilers do not achieve the efficiency of advanced implementation techniques as activity threads and integrated layer processing. The integration of these techniques into FDT compilers is difficult due to semantic constraints of the specification techniques and the lack of language features to flexibly adapt to a given implementation context. In this paper, we present the SDL compiler COCOS that provides such features. COCOS is a configurable compiler that includes different implementation techniques. Currently, it supports the server model and the activity thread model. COCOS possesses a variable implementation model that permits to adapt the code generation to the given implementation context. The adaption process is controlled by means of the implementation-oriented annotation iSDL which allows it to introduce implementation-related information into the specification. In the paper, we describe the motives for the design of COCOS and give an overview of its main features. We explain the inclusion of different implementation techniques and give examples for the use of iSDL. The measurements we present show that by applying the activity thread approach the efficiency of the generated code can be increased up to 50 per cent compared to the Cadvanced code generator of the SDT tool. Further, we show that by avoiding copy operations the efficiency of the generated code can be further increased.

COCOS - A configurable SDL compiler for generating efficient protocol implementations.

In this paper we propose a novel software-defined networking architecture for enterprise wireless local area networks (WLANs). The goal is to build a framework that exposes tools and methods for a centralized processing of IEEE 802.11 frames. In our architecture all management tasks, including beaconing, client authentication and association, are performed by the central controller instead of the distributed wireless access points as in traditional networks. The generated frames are tunneled to lightweight wireless access points (APs) or thin APs that perform the media access and radio frequency (RF) conversion. Agents executed on thin APs allow scheduling of simple tasks like traffic filtering for local execution. Additionally, the agents provide functions found in modern WLAN chipsets, such as precise frame transmit timings or RF spectrum analysis to the controller. Our architecture allows to delegate computationally intensive tasks to a central instance with enough processing power. Thus, it is best suited for devices with limited resources that we use as thin APs. We present applications that can be built using our framework, e.g., client geolocalization or energy consumption optimization. Finally we evaluate the performance of our architecture in a testbed using COTS devices with open-source software.

RADIator — An approach for controllable wireless networks

Applying UML diagrams for the design of dependable systems like communication protocols helps to visualize the protocol behavior in multiple representations. In principle, protocols are comprehensible by modeling its behaviors through sequence diagrams. However, the sequence diagrams encapsulate local protocol functions, such as protocol data unit coding/decoding, correctness checks, etc. To model the local actions of the protocol entities activity diagrams may be used as a balancing model. By using two different models, one should ensure that the described behaviors are consistent. To prove this we present an approach in this paper to synchronize the UML sequence and activity diagrams through mapping rules. The rules are predefined according to the UML specification by a stereotype. Later they are used for validating the two diagrams. We show the approach for an example protocol function.

An Approach to Synchronize UML-Based Design Components for Model-Driven Protocol Development

Low-rate and low-power wireless communications are still the main drivers for innovative industrial automation and the Internet of Things (IoT). Physical mobility is one of the most important challenges for them. Common wireless technologies and protocols, e.g., WirelessHART and ISA100.11a Wireless for industrial process plants, ZigBee for building automation, or 6LoWPAN and 6TiSCH in context of the IoT, are based on the IEEE 802.15.4 standard. Event-based simulation is the method of choice for analyzing network protocols and algorithmic applications of such distributed sensor applications. Performance measurements and holistic evaluations, however, are greatly influenced by the underlying hardware resources, physical layer protocols, and radio channel conditions, which are usually not considered or highly abstracted in network simulations. In this paper we present SEmulate, a hybrid system for seamless (network) simulation and hardware-based emulation for wireless sensor networks based on the IEEE 802.15.4 protocol standard, which takes the hardware aspects into account by applying an Hardware-in-the-Loop (HIL) approach.

SEmulate: Seamless Network Protocol Simulation and Radio Channel Emulation for Wireless Sensor Networks

The increasing use of wireless networks has raised the desire to have not only a stable and good quality access to the network, but also to seamlessly change the network when moving. Various handover algorithms have been proposed to handle this situation. Unfortunately, many of these handover algorithms have only been evaluated by simulations. They do not take the wide range of mobile devices with varying system parameters into account. For the practical deployment, handover algorithms are required that adapt to various device parameters and network characteristics. In this paper we present a fuzzy-based vertical handover decision algorithm which adjusts itself to the given device and network capabilities. Starting with a discussion of handover requirements we present the algorithm and describe how it is activated in the handover process. Finally we present several experiments which evaluate the accuracy of the handover decision, the quality of service guarantees for the application, and the resource consumption.

Hartmut Koenig

Papers

COCOS - A configurable SDL compiler for generating efficient protocol implementations.

RADIator — An approach for controllable wireless networks

An Approach to Synchronize UML-Based Design Components for Model-Driven Protocol Development

SEmulate: Seamless Network Protocol Simulation and Radio Channel Emulation for Wireless Sensor Networks

Towards a seamless mobility solution for the real world: Handover decision