A new interpolation error expansion based reversible watermarking algorithm considering the human visual system

Reversible watermarking has merged over the past few years as a promising solution for copyright protection, especially for applications like remote sensing, medical imaging and military applications which require lossless recovery of the host media. In this paper, we aim to extend the additive interpolation error expansion technique in [16]. We will consider the human visual system (HVS) to improve the embedding rate while maintaining the image visual quality. To this end, the just noticeable difference (JND) is used to embed more watermark bits. The experimental results show that the proposed algorithm can improve the embedding rate while preserving the image visual quality. © 2014 IEEE.

Histogram shape-based robust image watermarking method

Developing a watermarking method that is robust to cropping attack and random bending attacks (RBAs) is a challenging task in image watermarking. In this paper, we propose a histogram-based image watermarking method to tackle with both cropping attack and RBAs. In this method first the gray levels are divided into groups. Secondly the groups for watermark embedding are selected according to the number of pixels in them, which makes this method fully based on the histogram shape of the original image and adaptive to different images. Then the watermark bits are embedded by modifying the histogram of the selected groups. Since histogram shape is insensitive to cropping and independent from pixel positions, the proposed method is robust to cropping attack and RBAs. Besides, it also has high robustness against other common attacks. Experimental results demonstrate the effectiveness of the proposed method. © 2014 IEEE.

Robustness enhancement of quantization based audio watermarking method using adaptive safe-band

This paper presents a novel adaptive safe-band for quantization based audio watermarking methods, aiming to improve robustness. Considerable number of audio watermarking methods have been developed using quantization based techniques. These techniques are generally vulnerable to signal processing attacks. For these conventional quantization based techniques, robustness can be marginally improved by choosing larger step sizes at the cost of significant perceptual quality degradation. We first introduce fixed size safe-band between two quantization steps to improve robustness. This safe-band will act as a buffer to withstand certain types of attacks. Then we further improve the robustness by adaptively changing the size of the safe-band based on the audio signal feature used for watermarking. Compared with conventional quantization based method and the fixed size safe-band based method, the proposed adaptive safe-band based quantization method is more robust to attacks. The effectiveness of the proposed technique is demonstrated by simulation results. © 2014 IEEE.

Give back peace that will never end: Hibakusha poets as public intellectuals

Public Lecture as Visiting Scholar in Tokyo: 'Hibakusha as Public Intellectuals: Sadako Kurihara and Sankichi Toge and Genbaku Shisu'.

Network dynamics of mobile social networks

With the rapid development of smartphones and mobile Internet technology, we witness an overwhelming growth of mobile social networks (MSN), which is a type of social network, forming virtual communities among people with similar interests or commonalities. In MSNs, users play a crucial role for their development, deployment and success. Understanding the MSN user behavior therefore attracts interests of different entities - ISPs, service providers, and researchers. However, it is hard to gather a comprehensive real data set, little is known and even less has been published about MSN user activities. In this paper, we focus on analyzing MSN user behavior from the perspective of ISP network, which is seldom reported in literature. Based on the real data set collected from the mobile network gateway of a major mobile carrier who has more than five million subscribers, we present an in-depth user behavior analysis of four popular social networks. We study the MSN user behavior from six aspects: user requests, active online time, sessions, inter-session, the number of requests in a session, and inter-request. We found that power law and lognormal are two popular features of the studied objects, and exposed some interesting findings as well. We hope our work could be helpful for ISPs, MSN content providers, and researchers. © 2014 IEEE.

Detection on application layer DDoS using random walk model

Application Layer Distributed Denial of Service (ALDDoS) attacks have been increasing rapidly with the growth of Botnets and Ubiquitous computing. Differentiate to the former DDoS attacks, ALDDoS attacks cannot be efficiently detected, as attackers always adopt legitimate requests with real IP address, and the traffic has high similarity to legitimate traffic. In spite of that, we think, the attackers' browsing behavior will have great disparity from that of the legitimate users'. In this paper, we put forward a novel user behavior-based method to detect the application layer asymmetric DDoS attack. We introduce an extended random walk model to describe user browsing behavior and establish the legitimate pattern of browsing sequences. For each incoming browser, we observe his page request sequence and predict subsequent page request sequence based on random walk model. The similarity between the predicted and the observed page request sequence is used as a criterion to measure the legality of the user, and then attacker would be detected based on it. Evaluation results based on real collected data set has demonstrated that our method is very effective in detecting asymmetric ALDDoS attacks. © 2014 IEEE.

Byzantine-resilient secure software-defined networks with multiple controllers

Software-defined network (SDN) is the next generation of networking architecture that is dynamic, manageable, cost-effective, and adaptable, making it ideal for the high-bandwidth, dynamic nature of today's applications. In SDN, network management is facilitated through software rather than low-level device configurations. However, the centralized control plane introduced by SDN imposes a great challenge for the network security. In this paper, we present a secure SDN structure, in which each device is managed by multiple controllers rather than a single one as in a traditional manner. It can resist Byzantine attacks on controllers and the communication links between controllers and SDN switches. Furthermore, we design a cost-efficient controller assignment algorithm to minimize the number of required controllers for a given set of switches. Extensive simulations have been conducted to show that our proposed algorithm significantly outperforms random algorithms. © 2014 IEEE.

A clusterized firewall framework for cloud computing

Cloud computing is becoming popular as the next infrastructure of computing platform. However, with data and business applications outsourced to a third party, how to protect cloud data centers from numerous attacks has become a critical concern. In this paper, we propose a clusterized framework of cloud firewall, which characters performance and cost evaluation. To provide quantitative performance analysis of the cloud firewall, a novel M/Geo/1 analytical model is established. The model allows cloud defenders to extract key system measures such as request response time, and determine how many resources are needed to guarantee quality of service (QoS). Moreover, we give an insight into financial cost of the proposed cloud firewall. Finally, our analytical results are verified by simulation experiments.

Reproducibility of aortic intima-media thickness in infants using edge-detection software and manual caliper measurements

Background: Aortic intima-media thickness measured by transabdominal ultrasound (aIMT) is an intermediate phenotype of cardiovascular risk. We aimed to (1) investigate the reproducibility of aIMT in a population-derived cohort of infants; (2) establish the distribution of aIMT in early infancy; (3) compare measurement by edge-detection software to that by manual sonographic calipers; and (4) assess the effect of individual and environmental variables on image quality. Methods. Participants were term infants recruited to a population-derived birth cohort study. Transabdominal ultrasound was performed at six weeks of age by one of two trained operators. Thirty participants had ultrasounds performed by both operators on the same day. Data were collected on environmental (infant sleeping, presence of a sibling, use of sucrose, timing during study visit) and individual (post-conception age, weight, gender) variables. Two readers assessed image quality and measured aIMT by edge-detection software and a subset by manual sonographic calipers. Measurements were repeated by the same reader and between readers to obtain intra-observer and inter-observer reliability. Results: Aortic IMT was measured successfully using edge-detection in 814 infants, and 290 of these infants also had aIMT measured using manual sonographic calipers. The intra-reader intra-class correlation (ICC) (n = 20) was 0.90 (95% CI 0.76, 0.96), mean difference 1.5 μm (95% LOA -39, 59). The between reader ICC using edge-detection (n = 20) was 0.92 (95% CI 0.82, 0.97) mean difference 2 μm (95% LOA -45.0, 49.0) and with manual caliper measurement (n = 290) the ICC was 0.84 (95% CI 0.80, 0.87) mean difference 5 μm (95% LOA -51.8, 61.8). Edge-detection measurements were greater than those from manual sonographic calipers (mean aIMT 618 μm (50) versus mean aIMT 563 μm (49) respectively; p < 0.001, mean difference 44 μm, 95% LOA -54, 142). With the exception of infant crying (p = 0.001), no associations were observed between individual and environmental variables and image quality. Conclusion: In a population-derived cohort of term infants, aIMT measurement has a high level of intra and inter-reader reproducibility. Measurement of aIMT using edge-detection software gives higher inter-reader ICC than manual sonographic calipers. Image quality is not substantially affected by individual and environmental factors. © 2014 McCloskey et al.; licensee BioMed Central Ltd.

Dynamic weight-bearing assessment of pain in knee osteoarthritis: a reliability and agreement study

Purpose: To evaluate the reliability, agreement and smallest detectable change in a measurement instrument for pain and function in knee osteoarthritis; the Dynamic weight-bearing Assessment of Pain (DAP). Methods: The sample size was set to 20 persons, recruited from the outpatient osteoarthritis clinic at Frederiksberg Hospital, Copenhagen. Two physiotherapists tested all participants during two visits; at the first visit, one single DAP (including four scores) was conducted by rater one; at the second visit, DAP was conducted by both raters one and two in randomized order with concealed allocation. The time interval was approximately 1.5 h. Measurement error was estimated by standard error of measurement (SEM). The intra- and inter-rater reliability was estimated by Intra-class Correlation Coefficients for agreement based on a two-way ANOVA with random effects (single measures ICC 2.1). Smallest detectable change (SDC) and limits of agreement were calculated.Results: The pain score showed excellent reliability in terms of ICC (intra-rater 0.93, CI 0.83–0.97, inter-rater 0.91, CI 0.78–0.96), low SEM (intra-rater 0.70, inter-rater 0.86, on a scale from 0 to 10), and acceptable SDC for intra-rater test (1.95). The three knee bend scores all had ICC above 0.50, showing fair-to-good reliability. None of the knee bend scores showed acceptable SEM and SDC. Conclusions: The reproducibility of the DAP pain score meets the demands for use in clinical practice and research. The total knee bend could be useful for motivational purpose in clinical use. Testing of other psychometric properties of the DAP is pending.

Real-time ultrasound measures of lumbar erector spinae and multifidus: reliability and comparison to magnetic resonance imaging

In this work we examine the reliability and validity (in comparison to magnetic resonance imaging; MRI) of real-time ultrasound measures of lumbar erector spinae thickness. We also consider the between-day reliability of the lumbar multifidus muscle area as measured via ultrasound. 23 male subjects aged 21-45 years were measured three times over the course of nine days by one operator. The first (L1) through to the fifth (L5) lumbar vertebral levels were measured on the left and right sides. MRI was performed on the same day as first ultrasound scanning. For between-day intra-rater reliability, intra-class correlation co-efficients (ICCs), standard error of the measurement, minimal detectable difference and co-efficients of variation (CVs) were calculated along with their 95% confidence intervals and Bland-Altman analysis was performed. On Bland-Altman analysis, erector spinae thickness and multifidus area ultrasound measures 'agreed' with equivalent MR measures, though the correlation between MR and ultrasound measures was typically poor to moderate. For both ultrasound measures, the ICCs ranged from 'moderate' to 'excellent' at individual vertebral levels, although multifidus area (CV ranged from 8 to 15%) was less reliable than erector spinae thickness (CV ranged from 6 to 10%). 'Agreement' on Bland-Altmann analysis was present between days for all ultrasound measures. Averaging between sides and between vertebral levels improved reliability. Average erector spinae thickness showed a CV of 5.5% (ICC 0.77) and average multifidus area 6.2% (ICC 0.80).

Characterizing eating patterns: a comparison of eating occasion definitions

BACKGROUND: To date, many approaches have been used to define eating occasions (EOs). A standard definition for EOs is required to facilitate further research. OBJECTIVE: In this study, we examined the influence of differing definitions of EOs on the characterization of eating patterns. DESIGN: Cross-sectional dietary data from two 24-h recalls collected during the 2011-12 Australian National Nutrition and Physical Activity Survey (n = 5242 adults, aged ≥19 y) were analyzed. Eight definitions were applied: participant-identified, time-of-day, and 6 neutral definitions (individual EOs separated by different time intervals and/or an additional energy criterion of 210 kJ). Frequency of and total energy intake from meals, snacks, and all EOs were estimated, as appropriate. Differences were tested by using F tests, stratified by sex and age group. Agreement between different definitions of meal and snack frequencies was assessed by using intraclass correlation coefficients (ICCs). For each definition, linear regression was used to estimate the proportion of variance in total energy intake (kJ) and amount of food intake (g) predicted by frequency of EOs and meals and snacks. RESULTS: Among both sexes and across all age groups, mean frequencies of meals differed between the participant-identified and time-of-day definitions (mean difference range = 0.1-0.3; P < 0.001). There were statistically significant differences between mean frequencies of EOs across the 6 neutral definitions (P < 0.001). There was good agreement for snacks (men: ICC = 0.89; women: ICC = 0.87) but not meal frequencies (men: ICC = 0.38; women: ICC = 0.36) between the participant-identified and time-of-day definitions. The neutral definition (15-min time interval plus energy criterion) best predicted variance in total energy intake (R(2) range = 19.3-27.8). CONCLUSIONS: Different approaches to the definition of EOs affect how eating patterns are characterized, with the neutral definition best predicting variance in total energy intake. Further research that examines how different EO definitions affect associations with health outcomes is needed to develop consensus on a standard EO definition.

Fundamental movement skills are more than run, throw and catch: the role of stability skills

INTRODUCTION: In motor development literature fundamental movement skills are divided into three constructs: locomotive, object control and stability skills. Most fundamental movement skills research has focused on children's competency in locomotor and object control skills. The first aim of this study was to validate a test battery to assess the construct of stability skills, in children aged 6 to 10 (M age = 8.2, SD = 1.2). Secondly we assessed how the stability skills construct fitted into a model of fundamental movement skill. METHOD: The Delphi method was used to select the stability skill battery. Confirmatory factor analysis (CFA) was used to assess if the skills loaded onto the same construct and a new model of FMS was developed using structural equation modelling. RESULTS: Three postural control tasks were selected (the log roll, rock and back support) because they had good face and content validity. These skills also demonstrated good predictive validity with gymnasts scoring significantly better than children without gymnastic training and children from a high SES school performing better than those from a mid and low SES schools and the mid SES children scored better than the low SES children (all p < .05). Inter rater reliability tests were excellent for all three skills (ICC = 0.81, 0.87, 0.87) as was test re-test reliability (ICC 0.87-0.95). CFA provided good construct validity, and structural equation modelling revealed stability skills to be an independent factor in an overall FMS model which included locomotor (r = .88), object control (r = .76) and stability skills (r = .81). DISCUSSION: This study provides a rationale for the inclusion of stability skills in FMS assessment. The stability skills could be used alongside other FMS assessment tools to provide a holistic assessment of children's fundamental movement skills.

6 million spam tweets: a large ground truth for timely Twitter spam detection

Twitter has changed the way of communication and getting news for people's daily life in recent years. Meanwhile, due to the popularity of Twitter, it also becomes a main target for spamming activities. In order to stop spammers, Twitter is using Google SafeBrowsing to detect and block spam links. Despite that blacklists can block malicious URLs embedded in tweets, their lagging time hinders the ability to protect users in real-time. Thus, researchers begin to apply different machine learning algorithms to detect Twitter spam. However, there is no comprehensive evaluation on each algorithms' performance for real-time Twitter spam detection due to the lack of large groundtruth. To carry out a thorough evaluation, we collected a large dataset of over 600 million public tweets. We further labelled around 6.5 million spam tweets and extracted 12 light-weight features, which can be used for online detection. In addition, we have conducted a number of experiments on six machine learning algorithms under various conditions to better understand their effectiveness and weakness for timely Twitter spam detection. We will make our labelled dataset for researchers who are interested in validating or extending our work.

Development and interrater reliability of the UK Mental Health Triage Scale

Mental health triage scales are clinical tools used at point of entry to specialist mental health service to provide a systematic way of categorizing the urgency of clinical presentations, and determining an appropriate service response and an optimal timeframe for intervention. The aim of the present study was to test the interrater reliability of a mental health triage scale developed for use in UK mental health triage and crisis services. An interrater reliability study was undertaken. Triage clinicians from England and Wales (n = 66) used the UK Mental Health Triage Scale (UK MHTS) to rate the urgency of 21 validated mental health triage scenarios derived from real occasions of triage. Interrater reliability was calculated using Kendall's coefficient of concordance (w) and intraclass correlation coefficient (ICC) statistics. The average ICC was 0.997 (95% confidence interval (CI): 0.996-0.999 (F (20, 1300) = 394.762, P < 0.001). The single measure ICC was 0.856 (95% CI: 0.776-0.926 (F (20, 1300) = 394.762, P < 0.001). The overall Kendall's w was 0.88 (P < 0.001). The UK MHTS shows substantial levels of interrater reliability. Reliable mental health triage scales employed within effective mental health triage systems offer possibilities for not only improved patient outcomes and experiences, but also for efficient use of finite specialist mental health services.