Lightweight PUF based authentication scheme for fog architecture

Fog computing improves efficiency and reduces the amount of bandwidth to the cloud. In many use cases, the internet of things (IoT) devices do not know the fog nodes in advance. Moreover, as the fog nodes are often placed in open publicly available places, they can be easily captured. Therefore, it should be ensured that even if the key material is leaked from the fog devices, the previously generated session keys and the identity of the devices can be kept secret, i.e. satisfying anonymity, unlinkability, perfect forward secrecy and resistance against stolen devices attack. Such demands require a multi-factor authentication scheme, which is typically done by providing input of the user with password or biometric data. However, in real use case scenarios, IoT devices should be able to automatically start the process without requiring such manual interaction and also fog devices need to autonomously operate. Therefore, this paper proposes a physical unclonable function (PUF) based mutual authentication scheme, being the first security scheme for a fog architecture, capable of providing simultaneously all these suggested security features. In addition, we also show the resistance against other types of attacks like synchronization and known session specific temporary information attack. Moreover, the scheme only relies on symmetric key based operations and thus results in very good performance, compared to the other fog based security systems proposed in literature.

     

An SMVQ-based reversible data hiding technique exploiting side match distortion

Secure online communication is a necessity in today’s digital world. This paper proposes a novel reversible data hiding technique based on side match vector quantization (SMVQ). The proposed scheme classifies SMVQ indices as Case 1 or 2 based on the value of the first state codeword’s side match distortion (SMD) and a predefined threshold t. The proposed scheme uses this classification to switch between compression codes designed for Cases 1 and 2 SMVQ indices. The length of these compression codes is controlled by the parameter ?. Thus, with the selection of appropriate ? and t values, the proposed scheme achieves good compression, creating spaces to embed secret information. The embedding algorithm can embed n secret bits into each SMVQ index, where n = 1, 2, 3, or 4. The experimental results show that the proposed scheme obtains the embedding rates of 1, 2, 3, or 4 bit per index (bpi) at the average bit rates of 0.340, 0.403, 0.465, or 0.528 bit per pixel (bpp) for the codebook size 256. This improves the performance of recent VQ and SMVQ-based data hiding schemes.     

Environmental resilience and intergovernmental collaboration in the Pearl River Delta

Abstract

Water resource management is a crucial issue in the rapidly urbanizing Pearl River Delta. Numerous studies have examined transboundary water management, but those focusing on Hong Kong are largely technical, with little consideration for political dynamics or collaboration. This study’s contribution is a systematic analysis of water governance in China’s ‘one country–two systems’ setting. Through interviews and historical analysis, the study applies Ostrom’s Institutional Analysis and Development framework to a setting with political complexity and environmental vulnerability. The principal finding is that cooperation on supply infrastructure reflects a regional interdependence that builds the multiparty trust needed for more strategic governance.     

Measuring working memory load effects on electrophysiological markers of attention orienting during a simulated drive

Intersection accidents result in a significant proportion of road fatalities, and attention allocation likely plays a role. Attention allocation may depend on (limited) working memory (WM) capacity. Driving is often combined with tasks increasing WM load, consequently impairing attention orienting. This study (n = 22) investigated WM load effects on event-related potentials (ERPs) related to attention orienting. A simulated driving environment allowed continuous lane-keeping measurement. Participants were asked to orient attention covertly towards the side indicated by an arrow, and to respond only to moving cars appearing on the attended side by pressing a button. WM load was manipulated using a concurrent memory task. ERPs showed typical attentional modulation (cue: contralateral negativity, LDAP; car: N1, P1, SN and P3) under low and high load conditions. With increased WM load, lane-keeping performance improved, while dual task performance degraded (memory task: increased error rate; orienting task: increased false alarms, smaller P3).

Practitioner Summary: Intersection driver-support systems aim to improve traffic safety and flow. However, in-vehicle systems induce WM load, increasing the tendency to yield. Traffic flow reduces if drivers stop at inappropriate times, reducing the effectiveness of systems. Consequently, driver-support systems could include WM load measurement during driving in the development phase.     

Unsupervised document structure analysis of digital scientific articles

Text mining and information retrieval in large collections of scientific literature require automated processing systems that analyse the documents’ content. However, the layout of scientific articles is highly varying across publishers, and common digital document formats are optimised for presentation, but lack structural information. To overcome these challenges, we have developed a processing pipeline that analyses the structure a PDF document using a number of unsupervised machine learning techniques and heuristics. Apart from the meta-data extraction, which we reused from previous work, our system uses only information available from the current document and does not require any pre-trained model. First, contiguous text blocks are extracted from the raw character stream. Next, we determine geometrical relations between these blocks, which, together with geometrical and font information, are then used categorize the blocks into different classes. Based on this resulting logical structure we finally extract the body text and the table of contents of a scientific article. We separately evaluate the individual stages of our pipeline on a number of different datasets and compare it with other document structure analysis approaches. We show that it outperforms a state-of-the-art system in terms of the quality of the extracted body text and table of contents. Our unsupervised approach could provide a basis for advanced digital library scenarios that involve diverse and dynamic corpora.     

Kinetic studies of cationic photopolymerizations of cycloaliphatic epoxide,triethyleneglycol methyl vinyl ether,and cyclohexene oxide

The cationic photopolymerizations of monofunctional monomers and cycloaliphatic diepoxide monomer were examined in detail. Phenomenological kinetic models were developed for photopolymerizations of the monofunctional and difunctional monomers. For monofunctional monomers, the nonlinear models gave an excellent fit to the experimental data. Although a second‐order autocatalytic model was shown to be invalid above 10% conversion for the polymerization of a difunctional monomer (3,4‐epoxycyclohexylmethyl‐3′,4′‐epoxycyclohexane carboxylate, ECH), an autocatalytic model using diffusion‐controlled reaction with a Williams‐Landel‐Ferry (WLF) equation fits the experimental data well over the entire conversion range. A mechanistic model based on the free volume theory was also developed for cationic polymerization of the cycloaliphatic di‐epoxide monomer by using the method of moments. The model gives a good fit for the conversion and M_w development, but the calculated M_n results are lower than the experimental values. POLYM. ENG. SCI., 45:1546–1555, 2005. © 2005 Society of Plastics Engineers     

Single‐source dual‐layer amorphous IGZO thin‐film transistors for display and circuit applications

In this study, the authors report on high‐quality amorphous indium–gallium–zinc oxide thin‐film transistors (TFTs) based on a single‐source dual‐layer concept processed at temperatures down to 150°C. The dual‐layer concept allows the precise control of local charge carrier densities by varying the O₂/Ar gas ratio during sputtering for the bottom and top layers. Therefore, extensive annealing steps after the deposition can be avoided. In addition, the dual‐layer concept is more robust against variation of the oxygen flow in the deposition chamber. The charge carrier density in the TFT channel is namely adjusted by varying the thickness of the two layers whereby the oxygen concentration during deposition is switched only between no oxygen for the bottom layer and very high concentration for the top layer. The dual‐layer TFTs are more stable under bias conditions in comparison with single‐layer TFTs processed at low temperatures. Finally, the applicability of this dual‐layer concept in logic circuitry such as 19‐stage ring oscillators and a TFT backplane on polyethylene naphthalate foil containing a quarter video graphics array active‐matrix organic light‐emitting diode display demonstrator is proven.     

Atomic layer deposition enabled interconnect technology for vertical nanowire arrays

We have demonstrated an atomic layer deposition (ALD) enabled interconnect technology for vertical, c-axis oriented gallium nitride (GaN) nanowire (NW, 5–10 μm in length, 80–200 nm in diameter) arrays encapsulated by benzocyclobutene (BCB). The nano-scaled ALD multilayer is essential to provide conformal co-axial dielectric (ALD-alumina)/conductor (ALD-tungsten) coverage and precise thickness control for nanowire metallization. Furthermore, we have successfully developed a fabrication process to locally remove and connect tungsten (W) interconnect on NWs. Cross-sectional image taken in a focused ion beam (FIB) tool confirms the conformality of ALD interconnects. Photoluminescence (PL) wavelengths of the nanowires array can be tuned dynamically by changing the input current supplied to ALD-tungsten interconnect which heats nanowires. Such an experiment also demonstrated the quality of interconnect. This interconnect technology can be applied to various vertical nanowire-based devices, such as nanowire light emitting diodes, nanowire-based field effect transistors, resonators, batteries or biomedical applications.     

Sequential testing policies for complex systems under precedence constraints

We study the problem of sequentially testing the components of a multi-component system to learn the state of the system, when the tests are subject to precedence constraints and with the objective of minimizing the expected cost of the inspections. Our focus is on k-out-of-n systems, which function if at least k of the n components are functional. A solution is a testing policy, which is a set of decision rules that describe in which order to perform the tests. We distinguish two different classes of policies and describe exact algorithms (one branch-and-bound algorithm and one dynamic program) to find an optimal member of each class. We report on extensive computational experiments with the algorithms for representative datasets.