When and Where: Predicting Human Movements Based on Social Spatial-Temporal Events

Predicting both the time and the location of human movements is valuable but challenging for a variety of applications. To address this problem, we propose an approach considering both the periodicity and the sociality of human movements. We first define a new concept, Social Spatial-Temporal Event (SSTE), to represent social interactions among people. For the time prediction, we characterise the temporal dynamics of SSTEs with an ARMA (AutoRegressive Moving Average) model. To dynamically capture the SSTE kinetics, we propose a Kalman Filter based learning algorithm to learn and incrementally update the ARMA model as a new observation becomes available. For the location prediction, we propose a ranking model where the periodicity and the sociality of human movements are simultaneously taken into consideration for improving the prediction accuracy. Extensive experiments conducted on real data sets validate our proposed approach

Ocena postrzeganych zagrożeń środowiskowych dla życia mieszkańców w perspektywie środowiskowej opinii publicznej w Chinach

Population health, social development and the environment are important elements of sustainable development. This article uses the China People's Daily message board to collect environmental public opinion data, visualizes the public opinion hotspots of environmental based on word frequency statistics, and applies the Latent Dirichlet Allocations (LDA) topic model to analyze the spatial distribution of environmental risk perception dimensions. The conclusions are as follows: (1) in terms of the hotspots of environmental public opinion, the most frequent occurrences are the living environment, interest demands and noise pollution. (2) There is heterogeneity in the topic of environmental risk perception. The perception of pollution source types has the highest weight in environmental risk perception in the eastern, central, and western regions. Specifically, the types of pollution sources in the eastern that receive the most attention are garbage and noise pollution. In addition to paying attention to noise pollution, the central and western also have a higher perceived weight on the polluters. Residents in northeast are most concerned about changes in residents' health and living environment quality. (3) From the perspective of environmental risk perception, health perception has the highest proportion in northeast, followed by the eastern, and finally the central and western. Proportion of perception of interest demands is highest in the central region, perception of residential environment quality is highest in the northeast region, perception of pollution source types is highest in the eastern, central, and western regions, and lowest in the northeast region. Finally, some practical and feasible policy recommendations were proposed for different regions.Zdrowie ludności, rozwój społeczny i środowisko są ważnymi elementami zrównoważonego rozwoju. W tym artykule wykorzystano tablicę ogłoszeń China People's Daily do gromadzenia danych dotyczących opinii publicznej na temat środowiska, wizualizowano najważniejsze punkty opinii publicznej na temat środowiska w oparciu o statystyki częstotliwości słów i zastosowano model Latent Dirichlet Allocations (LDA) do analizy przestrzennego rozkładu wymiarów postrzegania ryzyka środowiskowego. Wnioski są następujące: (1) jeśli chodzi o najbardziej aktywne punkty opinii publicznej w zakresie ochrony środowiska, najczęstszymi zjawiskami są środowisko życia, wymagania dotyczące zainteresowań i zanieczyszczenie hałasem. (2) Istnieje różnorodność w temacie postrzegania ryzyka środowiskowego. Postrzeganie rodzajów źródeł zanieczyszczeń ma największe znaczenie w postrzeganiu ryzyka środowiskowego w regionach wschodnich, centralnych i zachodnich. W szczególności źródłami zanieczyszczeń we wschodniej części kraju, którym poświęca się najwięcej uwagi, są śmieci i hałas. Oprócz zwracania uwagi na zanieczyszczenie hałasem, regiony środkowe i zachodnie również przywiązują większą wagę do sprawców zanieczyszczeń. Mieszkańcy północno-wschodniej części kraju najbardziej niepokoją zmiany w ich zdrowiu i jakości środowiska życia. (3) Z punktu widzenia postrzegania ryzyka dla środowiska, postrzeganie zdrowia ma najwyższy odsetek na północnym wschodzie, następnie na wschodzie, a na końcu w środkowej i zachodniej części. Proporcja postrzegania potrzeb odsetkowych jest najwyższa w regionie centralnym, postrzeganie jakości środowiska mieszkalnego jest najwyższe w regionie północno-wschodnim, postrzeganie rodzajów źródeł zanieczyszczeń jest najwyższe w regionach wschodnich, centralnych i zachodnich, a najniższe w regionie północno-wschodnim. Na koniec zaproponowano kilka praktycznych i wykonalnych zaleceń politycznych dla różnych regionów

Non-Linearity Seepage Productivity Model and Influential Factors’ Analysis in Tight Sandstone Gas Reservoir

The tight sandstone gas is the most precious unconventional natural gas resource which has massive reserves all over the world. However, poor formation physical properties, extremely lower permeability, and complex pore-throat structure make it difficult to effective displacement in the tight gas formation. As a result, fracturing of horizontal wells is an effective technique for the tight gas. Based on the natural gas non-linearity unsteady seepage theory, the pseudo-pressure pattern and the overlay principle, this paper sets up the fractured horizontal well productivity model in the tight sandstone gas reservoir, which takes fracture interferences into consideration. Combined with the productivity model above, the relation curves between cumulative gas production and different factors have been drawn, and the sensitivity analysis of productivity influential factors has been carried on as well. Research shows that: the best length of horizontal well is 900 m and the corresponding optimal number of fractures is 6, while the optimal half-length of the fracture is 80 m. The length of horizontal well is the most sensitive influential factor to the productivity, while other factors are half-length of the fracture and the fracture conductivity in turn. Seeing from the sensitivity analysis curve, the fractured horizontal well productivity is not sensitive to fracture conductivity in tight gas formation. The study has an important guiding significance to productivity prediction and parameters optimization of fractured horizontal wells in the tight sandstone gas reservoir.Key words: Tight gas; Non-linearity seepage; Productivity prediction; Fractured horizontal wel

Empirical ResearchonTeaching KnowledgeSharingin University Townand Its Influential Factors

The implement of knowledge sharing in University Town facilitates to aggregate education resource and improve overall strength of University Town. According to factors and performance of teaching knowledge sharing in University Town, the model and theoretical hypothesis of teaching knowledge sharing in University Town are proposed. Questionnaire and structural equation model are used to empirically study teaching knowledge sharing model in University Town. The results indicate that three factors including the characteristics of knowledge, the cluster of University Town and the system and mechanism for University Town have a significant correlation with teaching knowledge sharing in University Town, while teaching knowledge sharing in University Town has a significant correlation with Knowledge Innovation, comprehensive strength and education quality of University Town. By analysis results, effective strategies are designed for knowledge sharing mechanism in University Town

A New Security Model for Cross-Realm C2C-PAKE Protocol

Cross realm client-to-client password authenticated key exchange (C2C-PAKE) schemes are designed to enable two clients in different realms to agree on a common session key using different passwords. In 2006, Yin-Bao presented the first provably secure cross-realm C2C-PAKE, which security is proven rigorously within a formally defined security model and based on the hardness of some computationally intractable assumptions. However, soon after, Phan et al. pointed out that the Yin-Bao scheme was flawed. In this paper, we first analyze the necessary security attributes in the cross-realm C2C-PAKE scenario, and then a new security model for cross-realm C2C-PAKE is given. Analogous to the general construction of 3PAKE protocol for single server C2C-PAKE setting, we give a general construction of cross-realm C2C-PAKE protocol, which security is proved in the new security model

Cryptanalysis of a client-to-client password-authenticated key agreement protocol

Recently, Byun et al. proposed an efficient client-to-client password-authenticated key agreement protocol (EC2C-PAKA), which was provably secure in a formally defined security model. This letter shows that EC2C-PAKA protocol is vulnerable to password compromise impersonate attack and man-in-the-middle attack if the key between servers is compromised

Simultaneous and Ultrasensitive Detection of Foodborne Bacteria by Gold Nanoparticles-Amplified Microcantilever Array Biosensor

Foodborne pathogens, especially bacteria, are explicitly threatening public health worldwide. Biosensors represent advances in rapid diagnosis with high sensitivity and selectivity. However, multiplexed analysis and minimal pretreatment are still challenging. We fabricate a gold nanoparticle (Au NP)-amplified microcantilever array biosensor that is capable of determining ultralow concentrations of foodborne bacteria including Escherichia coli O157:H7, Vibrio parahaemolyticus, Salmonella, Staphylococcus aureus, Listeria monocytogenes, Shigella, etc. The method is much faster than using conventional tools without germiculturing and PCR amplification. The six pairs of ssDNA probes (ssDNA1 + ssDNA2 partially complementary to the target gene) that originated from the sequence analysis of the specific gene of the bacteria were developed and validated. The ssDNA1 probes were modified with -S-(CH2)6 at the 5′-end and ready to immobilize on the self-assembled monolayers (SAMs) of the sensing cantilevers in the array and couple with Au NPs, while 6-mercapto-1-hexanol SAM modification was carried out on the reference cantilevers to eliminate the interferences by detecting the deflection from the environment induced by non-specific interactions. For multianalyte sensing, the target gene sequence was captured by the ssDNA2-Au NPs in the solution, and then the Au NPs-ssDNA2-target complex was hybridized with ssNDA1 fixed on the beam of the cantilever sensor, which results in a secondary cascade amplification effect. Integrated with the enrichment of the Au NP platform and the microcantilever array sensor detection, multiple bacteria could be rapidly and accurately determined as low as 1–9 cells/mL, and the working ranges were three to four orders of magnitude. There was virtually no cross-reaction among the various probes with different species. As described herein, it holds great potential for rapid, multiplexed, and ultrasensitive detection in food, environment, clinical, and communal samples

Robust Fuzzy Control for Fractional-Order Uncertain Hydroturbine Regulating System with Random Disturbances

The robust fuzzy control for fractional-order hydroturbine regulating system is studied in this paper. First, the more practical fractional-order hydroturbine regulating system with uncertain parameters and random disturbances is presented. Then, on the basis of interval matrix theory and fractional-order stability theorem, a fuzzy control method is proposed for fractional-order hydroturbine regulating system, and the stability condition is expressed as a group of linear matrix inequalities. Furthermore, the proposed method has good robustness which can process external random disturbances and uncertain parameters. Finally, the validity and superiority are proved by the numerical simulations