Long lasting instabilities in granular mixtures

We have performed experiments of axial segregation in the Oyama's drum. We have tested binary granular mixtures during very long times. The segregation patterns have been captured by a CCD camera and spatio-temporal graphs are created. We report the occurence of instabilities which can last several hours. We stress that those instabilities originate from the competition between axial and radial segregations. We put into evidence the occurence of giant fluctuations in the fraction of grain species along the surface during the unstable periods.Comment: 10 pages, 10 figures, (2002

Using Action Song to Improve the Ability in Using Punctuation Among Year Three Pupils

The purpose of this research was to investigate the use of action song to improve the USAge of punctuation among Year 3 pupils in a primary school in Johor. The whole class of eighteen pupils were selected as the target group. The teaching strategy comprised of the action song and the signs of punctuation marks such as full stop and comma. This study adopts a classroom action research. Tests, teacher's reflective journal and interview were used to gather the data for the study. The findings showed improvement when comparing the pupils' results in the tests before and after the implementation of action songs they were able to use the punctuations of full stop and comma correctly in the sentences. The findings also showed that the pupils were motivated to learn English and the strategy used improved the teacher's teaching practice. A few suggestions were given to improve the strategy for the next cycle of action research

Bacterial populations on silicone hydrogel and hydrogel contact lenses after swimming in a chlorinated pool

Purpose: A number of reports have indicated an association between swimming with contact lenses and subsequent eye infection. This study tests whether a hydrophilic contact lens worn while swimming accumulates bacteria present in the water. It was of interest to determine if lens type (silicone hydrogel versus hydrogel) affected the result. Methods: Fifteen healthy non-contact lens wearers swam for 30 minutes with a silicone hydrogel lens (Purevision) on one eye and a hydrogel lens (Acuvue 2) on the other. Lenses were removed aseptically and placed in sterile vials five minutes after the subjects left the water. Microbial growth was enumerated for total numbers of colonies and categorized by species present. Numbers of colonies were compared between the two lens groups, and with a water sample taken from the pool at the time of the experiment. Eight of the subjects returned on a different day and wore new lenses for thirty minutes under normal room conditions. Results: Two lenses were lost while swimming. 27 of the remaining 28 lenses worn while swimming showed colonization, principally with Staphylococcus epidermidis, which was also by far the most common species identified from the water itself. Small numbers of Staphylococcus aureus and Streptococcus salivarus were also present in both the water and on the lenses. Numbers of colonies varied among subjects (range 0-230), but no differences were observed between the two lens groups. Lenses removed after thirty minutes of wear without swimming were mostly sterile, with 3 of the 16 lenses showing just two colonies each. Conclusion: It appears that wearing a hydrophilic lens while swimming allows accumulation of microbial organisms on, or in, the lens, regardless of lens material. Swimmers should be advised to wear tight fitting goggles if lenses are worn while swimming, and thorough disinfection of the lenses prior to overnight wear seems prudent

Influence of supplementary cementitious materials on microstructure and transport properties of spacer-concrete interface

Reinforcement spacers are a critical component of concrete structures. Their presence affects microstructure and transport properties of concrete cover though this is not widely appreciated. This paper presents the first study to determine whether the negative effects of spacers can be mitigated through the use of supplementary cementitious materials such as silica fume, fly ash and blast-furnace slag. Concrete samples (>200) with different spacers, binders, curing and drying regimes were prepared and tested for diffusion, permeation, absorption, electrical conductivity, carbonation and microstructure. It was found that spacers increase all transport properties, the extent depending on type of spacer, drying regime and transport mechanism. The spacer-concrete interface is weak, porous and micro-cracked, and this lowers the resistance of concrete to ingress of aggressive agents. The beneficial effects of SCMs (strength enhancement and densification) and prolonged curing (120-day) are insufficient to overcome the negative effects of spacers. Implications for durability are discusse

BVPSMS: A Batch Verification Protocol for End-to-End Secure SMS for Mobile Users

Short Message Service (SMS) is a widely used communication medium for mobile applications, such as banking, social networking, and e-commerce. Applications of SMS services also include real-time broadcasting messages, such as notification of natural disasters and terrorist attacks, and sharing the current whereabouts to other users, such as notifying urgent business meeting information, transmitting quick information in the battlefield to multiple users, notifying current location to our friends, and sharing market information. However, traditional SMS is not designed with security in mind (e.g. messages are not securely sent). In this paper, we introduce a batch verification Authentication and Key Agreement (AKA) protocol, BVPSMS, which provides end-to-end message security over an insecure communication channel between different Mobile Subscribers (MSs). Specifically, the proposed protocol securely transmits SMS from one MS to multiple MS simultaneously. We then evaluate the performance of the BVPSMS protocol in terms of communication and computation overheads, protocol execution time, and batch and re-batch verification times. The impacts of the user mobility, and the time, space, and cost complexity analysis are also discussed. We present a formal proof of the proposed protocol. To the best of our knowledge, this is the first provably-secure batch verification AKA protocol, which provides end-to-end security to the SMS using symmetric keys

Raman spectroscopy of human teeth using integrated optical spectrometers

We have designed an arrayed-waveguide grating in silicon oxynitride technology for the detection of Raman signals from tooth enamel in the spectral region between 890 nm and 912 nm. The detected signals for both parallel and cross polarizations are used to distinguish between healthy and carious regions on the tooth surface of extracted human teeth. Our experimental results are in very good agreement with those achieved using conventional Raman spectrometers. Our results represent a step toward the realization of compact, hand-held, integrated spectrometers

Effect of Inflow and Infiltration in Sewerage System of Residential Area, Kuantan, Pahang

Inflow and infiltration is a phenomenon in sewerage systems that can have negative effects on the environment and human health if not treated properly. Collaboration has been made between Universiti Malaysia Pahang (UMP) and Indah Water Konsortium Sdn. Bhd. (IWK) where the purpose is to evaluate the amount of inflow and infiltration happening in sewerage systems of residential areas in Kuantan. For this part of the study, one sewer pipeline (MH92a–MH92b) was selected at the residential area of Bandar Putra, having a population equivalent of 1694. The method used in this research was the Flowrate method to tabulate data. ISCO 2150 and 4250 Area Velocity Flowmeters were used to measure flow rate data in the sewer pipeline, whereas ISCO 674 Rain Gauge was used to collect rainfall intensity data. Calibration of all the equipment was done at the Hydrology and Hydraulic Laboratory in UMP. The data was collected for 41 days with each measurement separated by an interval of five minutes. The result shows that the average percentage Infiltration Rate of Qpeak and Qave in this residential catchment were 10.3% and 26.5% which is higher than the value mentioned in Hammer and Hammer (2012). Inflow and infiltration is a real concern, so more study is required to determine whether revision of the infiltration rate recommended in the Malaysian Standard is needed

Impact and key challenges of insider threats on organizations and critical businesses

The insider threat has consistently been identified as a key threat to organizations and governments. Understanding the nature of insider threats and the related threat landscape can help in forming mitigation strategies, including non-technical means. In this paper, we survey and highlight challenges associated with the identification and detection of insider threats in both public and private sector organizations, especially those part of a nation’s critical infrastructure. We explore the utility of the cyber kill chain to understand insider threats, as well as understanding the underpinning human behavior and psychological factors. The existing defense techniques are discussed and critically analyzed, and improvements are suggested, in line with the current state-of-the-art cyber security requirements. Finally, open problems related to the insider threat are identified and future research directions are discussed

Psychological Safety and Norm Clarity in Software Engineering Teams

In the software engineering industry today, companies primarily conduct their work in teams. To increase organizational productivity, it is thus crucial to know the factors that affect team effectiveness. Two team-related concepts that have gained prominence lately are psychological safety and team norms. Still, few studies exist that explore these in a software engineering context. Therefore, with the aim of extending the knowledge of these concepts, we examined if psychological safety and team norm clarity associate positively with software developers' self-assessed team performance and job satisfaction, two important elements of effectiveness. We collected industry survey data from practitioners (N = 217) in 38 development teams working for five different organizations. The result of multiple linear regression analyses indicates that both psychological safety and team norm clarity predict team members' self-assessed performance and job satisfaction. The findings also suggest that clarity of norms is a stronger (30\% and 71\% stronger, respectively) predictor than psychological safety. This research highlights the need to examine, in more detail, the relationship between social norms and software development. The findings of this study could serve as an empirical baseline for such, future work.Comment: Submitted to CHASE'201

Guidance in the human–machine analytics process

In this paper, we list the goals for and the pros and cons of guidance, and we discuss the role that it can play not only in key low-level visualization tasks but also the more sophisticated model-generation tasks of visual analytics. Recent advances in artificial intelligence, particularly in machine learning, have led to high hopes regarding the possibilities of using automatic techniques to perform some of the tasks that are currently done manually using visualization by data analysts. However, visual analytics remains a complex activity, combining many different subtasks. Some of these tasks are relatively low-level, and it is clear how automation could play a role—for example, classification and clustering of data. Other tasks are much more abstract and require significant human creativity, for example, linking insights gleaned from a variety of disparate and heterogeneous data artifacts to build support for decision making. In this paper, we outline the potential applications of guidance, as well as the inputs to guidance. We discuss challenges in implementing guidance, including the inputs to guidance systems and how to provide guidance to users. We propose potential methods for evaluating the quality of guidance at different phases in the analytic process and introduce the potential negative effects of guidance as a source of bias in analytic decision making