Impact of Asian continental outflow on the concentrations of O3, CO, NMHCs and halocarbons on Jeju Island, South Korea during March 2005

As part of ABC-EAREX2005 experiment, numerous trace gases were measured at Gosan on Jeju Island, South Korea in March 2005 to characterize the impact of recent outflow from the Asian continent and to inter-compare measurement techniques used by participating groups. Here we present measurements of O3, CO, and whole air samples of methane, C2-C8 non-methane hydrocarbons (NMHCs) and C1-C2 halocarbons obtained during the study. The large temporal variations in the measured trace gas concentrations at Gosan were due to the transport of background marine air and of regional pollution mainly from the Chinese subcontinent. Average mixing ratios (± s.d.) were 54.6 (± 9.0) ppbv and 283 (± 100) ppbv for O3 and CO, respectively. CO showed good correlations (r2 = 0.62-0.81) with combustion tracers such as ethyne and benzene but poorly correlated (r2 = 0.11-0.29) with light alkanes, suggesting that the latter were contributed by non-combustion source(s). Back trajectory analysis showed that air masses mainly originated from the North China Plains and northeastern China, which together accounted for 64% of the total trajectories. The highest mean mixing ratios of O3 and combustion-derived species were found in air masses from eastern China and Korea, indicating the significant impact of emissions from these regions. Interestingly, air masses from northeast China contained elevated levels of light alkanes and the smallest ratios of ethyne/propane and benzene/propane among the air-mass groups, suggesting contribution from natural gas leakage in the upwind region, possibly from Siberia. © 2007 Elsevier Ltd. All rights reserved

Countering Social Engineering through Social Media: An Enterprise Security Perspective

The increasing threat of social engineers targeting social media channels to advance their attack effectiveness on company data has seen many organizations introducing initiatives to better understand these vulnerabilities. This paper examines concerns of social engineering through social media within the enterprise and explores countermeasures undertaken to stem ensuing risk. Also included is an analysis of existing social media security policies and guidelines within the public and private sectors.Comment: Proceedings of The 7th International Conference on Computational Collective Intelligence Technologies and Applications (ICCCI 2015), LNAI, Springer, Vol. 9330, pp. 54-6

A Low Complexity Pilot Scheduling Algorithm for Massive MIMO

Pilot contamination is a fundamental bottleneck in massive multiple-input multiple-output (MIMO) cellular networks. In this letter, we aim to design a pilot scheduling method to reduce the effect of pilot contamination in multi-user multi-cell massive MIMO systems. Mathematically, the pilot scheduling problem can be formulated as a permutation-based optimization problem. However, finding the optimal solution requires an exhaustive search and is computationally prohibitive. Therefore, we propose a low-complexity near-optimal algorithm developed from the cross-entropy optimization framework to solve this problem. Simulation results reveal that our algorithm not only significantly outperforms the existing pilot-scheduling schemes but also achieves excellent performance with low complexity

Characterizing the overlap between SLI and dyslexia in Chinese: The role of phonology and beyond

This study examined the overlap of dyslexia and specific language impairment (SLI) in Cantonese-Chinese-speaking children. Thirty children with a prior diagnosis of SLI and 9 normal controls, aged between 6;0 and 11;3, participated. The children with SLI were tested for language impairment and dyslexia. Seven retained a diagnosis of SLI but were dyslexia-free (SLI-only), 13 received a comorbid diagnosis of dyslexia (SLI-D), and SLI had become history (SLI-H) in the other 10 children with no co-morbid diagnoses of dyslexia. The SLI-only group did worse on textual comprehension, but better on left-right reversal (an orthographic skill), than the SLI-D group. The SLI-only and the SLI-D group shared the same range of cognitive deficits relative to age norms and showed no difference in phonological processing. The SLI-D group did worse than the normal group on phonological representation, and both the SLI-only and the SLI-D group had difficulties with morphological awareness. © 2010 Society for the Scientific Study of Reading.postprin

Determining the slag fraction, water/binder ratio and degree of hydration in hardened cement pastes

A method for determining the original mix composition of hardened slag-blended cement-based materials based on analysis of backscattered electron images combined with loss on ignition measurements is presented. The method does not require comparison to reference standards or prior knowledge of the composition of the binders used. Therefore, it is well-suited for application to real structures. The method is also able to calculate the degrees of reaction of slag and cement. Results obtained from an experimental study involving sixty samples with a wide range of water/binder (w/b) ratios (0.30 to 0.50), slag/binder ratios (0 to 0.6) and curing ages (3 days to 1 year) show that the method is very promising. The mean absolute errors for the estimated slag, water and cement contents (kg/m3), w/b and s/b ratios were 9.1%, 1.5%, 2.5%, 4.7% and 8.7%, respectively. 91% of the estimated w/b ratios were within 0.036 of the actual values

Status of six non-native marine species in the coastal environment of Hong Kong, 30 years after their first record

This is the first systematic assessment conducted on fouling communities to determine the current status of six non-native marine invertebrates that were first recorded in Hong Kong three decades ago. They include the solitary ascidian, Ciona intestinalis; the slipper limpet, Crepidula onyx; the bryozoan, Bugula californica; the Caribbean bivalve, Mytilopsis sallei; the Mediterranean mussel, Mytilus galloprovincialis; and the boring isopod, Sphaeroma walkeri. Field surveys were conducted at 31 locations during wet (2011) and dry (2012) seasons and included fouling communities on piers and mariculture zones from estuarine to oceanic zones. The sampling was conducted by using photo-quadrats, destructive quadrats and field observations. To detect temporal changes in the abundance and recruitment of the sedentary non-native species, three piers were monitored with permanent photo-quadrats and recruitment panels for a one year period. We examined the relationship between seawater quality data available for Hong Kong and the abundances of fouling and non-native species. Only four of the six target non-native species were recorded in this survey. The isopod Sphaeroma walkeri was common and widely distributed in fouling communities in Hong Kong, while Ciona intestinalis, Crepidula onyx, and Mytilopsis sallei were uncommon and mainly restricted to areas with intensive human activities and poor seawater quality. These findings suggest that near shore human activities and poor water quality could increase the risk of establishment of non-native species in Hong Kong’s marine fouling communities.published_or_final_versio

On Sparse Vector Recovery Performance in Structurally Orthogonal Matrices via LASSO

In this paper, we consider the compressed sensing problem of reconstructing a sparse signal from an undersampled set of noisy linear measurements. The regularized least squares or least absolute shrinkage and selection operator (LASSO) formulation is used for signal estimation. The measurement matrix is assumed to be constructed by concatenating several randomly orthogonal bases, which we refer to as structurally orthogonal matrices. Such measurement matrix is highly relevant to large-scale compressive sensing applications because it facilitates rapid computation and parallel processing. Using the replica method in statistical physics, we derive the mean-squared-error (MSE) formula of reconstruction over the structurally orthogonal matrix in the large-system regime. Extensive numerical experiments are provided to verify the analytical result. We then consider the analytical result to investigate the MSE behaviors of the LASSO over the structurally orthogonal matrix, with an emphasis on performance comparisons with matrices with independent and identically distributed (i.i.d.) Gaussian entries. We find that structurally orthogonal matrices are at least as good as their i.i.d. Gaussian counterparts. Thus, the use of structurally orthogonal matrices is attractive in practical applications

Key management issues in wireless sensor networks : current proposals and future developments

Author name used in this publication: Henry C. B. Chan2007-2008 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Family Financial Pressure in Childhood and Telomere Length in Early Adolescence: A Prospective Study

Much research on children in high-risk environments has focused on the biological consequences of maltreatment, adversity, and trauma. Whether other early-life stress sources such as family financial hardship are implicated in the cellular mechanism of disease development remains unclear. This study investigated the long-term effect of childhood exposure to family financial pressure on telomere length. It involved two waves of data collection occurring when participants reached Grade 3 (W1) and 7 (W2), respectively. In W1, parents reported family demographics and perceived financial stressors and pressure. In W2, participants provided buccal swab samples for measurement of their telomere length. Data from 92 participants (Mage in W2 = 13.2 years; 56.5% male) were analyzed. The main type of stressors reported by parents who perceived high family financial pressure in W1 were child-level stressors including affordability of their medical and educational expenses. Participants exposed to high parent-perceived family financial pressure in W1 had shorter telomeres in W2 when compared to those exposed to low parent-perceived family financial pressure (β = −0.61, p = 0.042). Subgroup analyses revealed stronger associations in girls than boys. These findings reveal an important spillover effect between parental financial perceptions and stress and children’s health at the cellular level

(Dis)connections between specific language impairment and dyslexia in Chinese

Poster Session: no. 26P.40Specific language impairment (SLI) and dyslexia describe language-learning impairments that occur in the absence of a sensory, cognitive, or psychosocial impairment. SLI is primarily defined by an impairment in oral language, and dyslexia by a deficit in the reading of written words. SLI and dyslexia co-occur in school-age children learning English, with rates ranging from 17% to 75%. For children learning Chinese, SLI and dyslexia also co-occur. Wong et al. (2010) first reported on the presence of dyslexia in a clinical sample of 6- to 11-year-old school-age children with SLI. The study compared the reading-related cognitive skills of children with SLI and dyslexia (SLI-D) with 2 groups of children …postprin