Miracle-dz/UniFAR-FTUs huggingface dataset:
Loitering behavior detection by spatiotemporal characteristics quantification based on the dynamic features of Automatic Identification System (AIS) messages

The capability of the Automatic Identification System (AIS) to provide real-time worldwide coverage of ship tracks has made it possible for maritime authorities to utilize AIS as a means of surveillance to identify anomalies. Anomaly detection in maritime traffic is crucial as anomalous behavior may be a sign of either emergencies or illegal activities. Anomalous ships are recognized based on their behavior by manual examination. Such work requires extensive effort, especially for nationwide surveillance. To deal with this, researchers proposed computational methods to analyze vessel behavior. However, most approaches are region-dependent and require a profile of normality to detect anomalies, and amongst the six types of anomaly, loitering is the least explored. Loitering is not necessarily anomalous behavior as it is common for certain types of ships, such as pilot boats and research vessels. However, tankers and cargo ships normally do not engage in loitering. Based on 12-month manually examined data, nearly 60% of the identified anomalies were loitering, particularly for those of types cargo and tanker. Although manual identification is inefficient, automatically identifying abnormal vessels by merely implementing computing algorithms is not yet feasible. It still needs subject matter experts’ assessments. This study proposes a region-independent method to automatically detect loitering without training normal instances and produces a ranked list of loitering vessels to facilitate further anomaly investigation. First, the loitering spatiotemporal characteristics are defined: (1) movement of frequent course change, with a certain speed, within a certain spatial range, (2) movement of frequent course change within traversed geodetic distance, (3) might demonstrate frequent extreme turning, and (4) extreme turning produces a significant discrepancy between the course over ground and the heading of the ship. Then, the characteristics are quantified by manipulating the dynamic information of AIS messages. Finally, the parameters to determine a loitering trajectory are formulated by comparing the rate of course change, speed, and the discrepancy between heading and course with the area of spatial range enclosing the trajectory and the geodetic distance between the start and end point. The loitering score of each trajectory is calculated with the parameters, and the Isolation Forest algorithm is employed to establish a threshold and rank. Then, geographic visualization is created for intuitive evaluation. An experiment was conducted on a real-world dataset covering a sea area of 610,116.37 km2. The results prove the efficacy of the proposed method. It remarkably outperforms the existing approach with 97% accuracy and 92% F-score. The experiment produces a ranked list of loitering vessels and an intuitive visualization in the relevant geographic area. In the realworld scenario, they are practical means to support further examination by human operators.
A Kinematics-Based Probabilistic Roadmap Method for Closed Chain Systems

In this paper we consider the motion planning problem for closed chain systems with a mobile base. We propose an extension of the prmmethodology which uses the kinematics of the closed chain system to guide the generation and connection of closure congurations. In particular, we break the closed chains into a set of open chains, apply standard prm random sampling techniques and forward kinematics to one subset of the subchains, and then use inverse kinematics on the remaining subchains to enforce the closure constraints. This strategy preserves the PRM sampling philosophy, while addressing the fact that the probability that a random con guration will satisfy the closure constraints is zero, which has proven problematical in previous attempts to apply the PRM methodology to closed chain systems. Another distinguishing feature of our approach is that we adopt a two-stage strategy, both of which employ the prm framework. First, we disregard the environment, x the position and orientation of one link of the chain, and construct a kinematic roadmap which contains di erent self-collision-free closure con gurations. Next, we populate the environment with copies of the kinematic roadmap (nodes and edges), and then use rigid body planners to connect con gurations of the same closure type. This two-stage approach enables us to amortize the cost of computing and connecting closure con gurations. Our results in 3-dimensional workspaces show that good roadmaps for closed chains with many links can be constructed in a few seconds as opposed to the several hours required by the previous purely randomized approach. Figure 1: The Stanford Assistant Mobile Manipulator [13]. (Photo Courtesy of Prof. Oussama Khatib.)
On improving the simulation of Atlantic Water circulation in the Arctic Ocean

[1] We performed a set of numerical experiments in order to better simulate the circulation of Atlantic Water in the Arctic Ocean by employing a coupled ice-ocean Arctic regional model. We found that the inflow of Atlantic Water via Fram Strait is weak in the case of high viscosity and diffusivity coefficients (1 · 108 cm2/s and 1 · 107 cm2/s) and creates an anticyclonic circulation in the Eurasian basin. This flow increases significantly when both coefficients are scaled down (to 1 · 107 cm2/s and 0.5 · 106 cm2/s) but the current path is then unstable, and it becomes mostly anticyclonic after about a decade of integration. A further reduction of these coefficients leads to growing instabilities due to insufficient grid resolution. Short-term integration of the model with doubled space resolution shows better agreement with observations, but long-term calculation is still restricted by simulation time. Alternatively, a lower resolution version of this model benefits from parameterizations of subscale processes. Incorporation of the Neptune parameterization of eddy-topography interaction into the model intensifies the current steered by subsurface topography and results in cyclonic circulation of the Atlantic Water in every subbasin and in the whole Arctic region. In the absence of salinity restoring there was strong salinity drift at the surface, resulting in a salinity increase in the central Arctic by 3 units from 1960 to 2005. The Arctic freshwater content is driven basically by year-to-year variations of convective mixing involving more saline water from lower layers. After cooling and increasing in salinity through brine rejection, the surface water becomes denser, leading to even stronger convective mixing. One-dimensional model tests showed how model performance could be improved by implementing a lower vertical diffusion coefficient and higher vertical resolution.
Concession length and investment timing flexibility

When assigning a concession contract, the regulator faces the issue of setting the concession length. Another key issue is whether or not the concessionaire should be allowed to set the timing of new investments. In this paper we investigate the impact of concession length and investment timing flexibility on the “concession value. ” It is generally argued that long‐term contracts are privately valuable as they enable a concessionaire to increase its overall discounted returns. Moreover, the real option theory suggests that investment flexibility has an intrinsic value, as it allows concessionaires to avoid costly errors. By combining these two conventional wisdoms one may argue that long‐term contracts, which allow for investment timing flexibility, should always result in higher concession values. Our result suggests that this is not always the case; that is, investment flexibility and long‐term contracts do not necessarily increase the concession value.
3D free‐boundary conditions for coordinate‐transform finite‐difference seismic modelling

New alternative formulations of exact boundary conditions for arbitrary three‐dimensional (3D) free‐surface topographies on seismic media have been derived. They are shown to be equivalent to previously published formulations, thereby verifying the validity of each set of formulations. The top of a curved grid represents the free‐surface topography while the interior of the grid represents the physical medium. We assume the velocity–stress version of the viscoelastic wave equations to be valid in this grid before transforming the equations to a rectangular grid. In order to perform the numerical discretization we apply the latter version of the equations for seismic wave propagation simulation in the medium. The numerical discretization of the free‐surface topography boundary conditions by second‐order finite differences (FDs) is shown, as well as the spatially unconditional stability of the resulting system of equations. The FD order is increased by two for each point away from the free surface up to eight, which is the order used in the interior. We use staggered grids in both space and time and the second‐order leap‐frog and Crank– Nicholson methods for wavefield time propagation. An application using parameters typical of teleseismic earthquakes and explosions is presented using a 200 × 100 km2 area of real topography from southwestern Norway over a homogeneous medium. A dipping plane wave simulates a teleseismic P‐wave incident on the surface topography. Results show conversion from P‐ to Rg‐ (short period fundamental mode Rayleigh) waves in the steepest and/or roughest topography, as well as attenuated waves in valleys and fjords. The codes are parallelized for simulation on fast supercomputers and PC‐clusters to model high frequencies and/or large areas.
Dynamic behavior of coastal sediment

The study of coastal sediment processes was carried out initially by coastal geomorphologists in the past century. However, the dynamics of nearshore sediment movement has been treated by researchers in the fields of coastal engineering and nearshore oceanography over the past half century. The aim of this paper is to review the achievement of the related researches up to the present and to suggest finally the subjects which should be studied more deeply in the near future. This review article covers 1) the significance of coastal sediment study as an introduction, 2) an outline of coastal sediment behavior, 3) the critical water depth for the inception of sediment movement, 4) various modes of coastal sediment movement, 5) numerical simulation models of beach transformation, and 6) conclusions and recommendations for future studies. (Communicated by Takao INUI, M.J.A.)
Impact of atmospheric aerosol light scattering and absorption on terrestrial net primary productivity

Scattering and absorption of sunlight by anthropogenic aerosols reduce the photosynthetically active radiation (PAR) incident upon the Earth's surface, but increase the fraction of the PAR that is diffuse. These alterations to irradiance may elicit conflicting responses in terrestrial plants: photosynthesis and net primary productivity (NPP) are slowed by reductions in total PAR, but enhanced by increases in diffuse PAR. In this paper, we use two canopy photosynthesis models to estimate the net effect of aerosols on carbon assimilation by green plants during summertime at midlatitudes. The model calculations indicate that the net effect of PAR scattering and absorption by atmospheric aerosols on NPP can be positive, neutral, or negative. Two parameters that strongly influence the net effect are the aerosol optical depth (integral of light extinction with height) and the cloud cover. On cloudless days NPP peaks under moderately thick aerosol loadings. On overcast days, aerosols slow NPP. The implications of these results for various regions of the globe and possible directions for future studies on the effect of aerosols on plant growth are discussed.
Estimation of Un-electrified Households a Electricity Demand for Planning Electrification of Un-electrified Areas : Using South Africa as Case

“We emphasize the need to address the challenge of access to sustainable modern energy services for all, in particular for the poor, who are unable to afford these services even when they are available. ” Section 126: The Future We Want (Out Come Document of Rio+20-United Nations Conference on Sustainable Development June 20-22, 2012). The lack of energy access has been identified as a hurdle in achieving the United Nations’ Millennium Development Goals, leading towards the urge to set a goal for universal electrification till 2030. With around 600 million people in Africa without access to electricity, effective and efficient electrification programs and policy framework is required to achieve this goal sustainably.South Africa is an example in the continent for initiating intense electrification programs and policies like “Free Basic Electricity”, increasing its electrification rate from 30% in 1993 to 75% in 2010 and a claimed 82% in 2011. The case of South Africa has been analysed from the perspective of universal electrification in the coming years. The aim was to estimate the un-electrified households for each area of South Africa in order to provide the basis for electrification planning. The idea was to use available electrification statistics with GIS (Geographic Information System) maps for grid lines and identifying the suitability of on-grid or off-grid electrification options, which may help in planning the electrification of these areas in the near future. However, due to lack of readily available data, the present work has been able to estimate the un-electrified households & their possible electrical load. The estimates have been distributed in different income groups for each province and district municipality of South Africa, which can be used for electrification planning at national, provincial and municipal level. As a result, some simple and useful data parameters have been identified and an estimation methodology has been developed, which may be employed to obtain similar estimates at lower administrative levels i.e. local municipalities and wards.The work can be utilized further and feasible electrification options may be suggested for different areas of South Africa, with the help of GIS maps and data. Depending on the availability of useful data, the data parameters & indicators used in this work will be helpful for planning the electrification for rural households in other places of Africa.
Medieval landscapes and lordship in South Uist

This thesis examines the structures of society and lordship in the Middle Ages in South Uist through historical documentation, oral-tradition, cultural landscapes, monuments and settlement patterns. In this thesis, the medieval period has been defined as that between c. 1000 and c. 1650. The historical evidence is considered along with archaeological evidence to create a holistic understanding of medieval social developments in South Uist. The results have ramifications for interpreting contemporaneous society throughout Scotland and Ireland. The study focuses on rural settlement (farms, townships, field- and transhumance-systems) and high-status monuments (churches, duns and castles). Developments visible in both the historical and archaeological record demonstrate that considerable social, economic and cultural changes took place within the landscape of South Uist throughout the Middle Ages. However, the nature of the evidence polarises the study into two time spheres: the Norse period, c. 1000 - c. 1400, and the Late Medieval period, c. 1550 - c. 1650. Remains belonging to the intervening period have proved difficult to locate. The Norse period landscape was characterised by dispersed farmsteads, possibly siting within an enclosed field-system. It is probable that these farmsteads originated as the homesteads of Viking Age settlers. Between the eleventh century and the end of the 1300s, there was a trend towards social and economic centralisation and the creation of an increasingly formalised social hierarchy: manifestations of this can be seen in the archaeological record and a new system of taxation. Archaeologically this is revealed by increasing divergence in the sizes of farmsteads, the largest of which also exhibit signs of industrial and agricultural control. Increased social differentiation is additionally reflected in artefact assemblages.
Left-behind children in rural China : research based on the use of qualitative methods in Inner Mongolia

There is a dearth of knowledge about the experiences of primary school aged left-behind children in the family, school and the community. The term “left-behind children” has occurred in a variety of literature in China since the end of 1980s when the huge population flows from rural areas to urban areas began. A review of the existing research literature suggests that emergence of left-behind children in China is the result of some unique features of rural migration to the cities in China. Their parents’ migration has a significant impact on their welfare and wellbeing in every respect. The overall aim of this research is to explore the experiences of children’s being left behind at home, at school and in the community from the perspectives of four main groups of stakeholders: left-behind children, their guardians, their parents and their teachers. This thesis challenges the view of left-behind children as an event, but instead argues that it is a dynamic process of choice and change with a variety of outcomes. As this is only a small scale survey with the intention of exploring whether the more detailed case studies are typical of the experiences of a wider group of children, in-depth interviews were undertaken with twelve left-behind children and one not-left-behind child in three different stages. The research suggests that negative effects of their parents’ migration can also be seen to be cumulative and to create a negative ‘trajectory’ through which momentum for change developed, developments which seemed impossible to resist. However, both left-behind children and their parents are not always passive victims of the adverse outcomes. A number of parents make complex assessments of the child’s well-being and negotiate with carers and potential carers.
Dynamics of Intraseasonal Sea Level Variations Observed at Gan Island and Sibolga

Dynamics of intraseasonal sea level variability in the central and eastern equatorial Indian Ocean is examined using 66 months (1 January 1993 to 30 June 1998) of the observed sea level at Gan Island (0 °41'S, 73 °E) and Sibolga (1 °45'N, 98 °46'E). The analysis shows that the intraseasonal signals of 20-100-day at those two tidal stations are coherent and exhibit eastward energy propagation. These intraseasonal variations are associated with the propagation of equatorial Kelvin waves generated by the zonal winds along the equator. The lag-correlation analysis reveals that their phase speed is closed to the theoretical phase speed of the first and second baroclinic modes of the Kelvin waves.
An isomorphism theorem for random interlacements

We consider continuous-time random interlacements on a transient weighted graph. We prove an identity in law relating the field of occupation times of random interlacements at level u to the Gaussian free field on the weighted graph. This identity is closely linked to the generalized second Ray-Knight theorem, and uniquely determines the law of occupation times of random interlacements at level u.
RemOrphan: Object Storage Sustainability Through Removing Offline-Processed Orphan Garbage Data

Nowadays, extremely large amounts of structured and unstructured types of data are stored in public, private, and hybrid cloud storage using object storage systems. Among these, storing multimedia data such as image, video, and audio pose unique challenges and long-term effects on object storage Sustainability. Three such challenges are smoother and more efficient video streaming, middleware placement for media processing, and lastly, management of orphan garbage data. In order to tackle these challenges, this paper presents a generalized architecture for smooth and efficient management as well as retrieval of multimedia data in cloud systems. To do so, first, we propose a new middleware package in the object server for supporting smooth video streaming and on-demand playable video segments. Here, we demonstrate that video segment download time improves by up to 30% when segmentation is done in the object server rather than in the proxy server. After, we focus on how to find orphan garbage data on media cloud storage and to what extent they can hamper data retrieval. Specifically, we present a generalized architecture named ‘RemOrphan’ for detecting the orphan garbage data using OpenStack Swift hash Ring and scripts. We deploy a private media cloud SPMS and find that around 35% data can be orphan garbage data. Due to the huge amount of orphan data, rsync replication needs higher time and more network overhead which hampers the system’s sustainability. We lower around 25% sync delay and 30% network overhead after deploying a deletion daemon to remove the orphan garbage data.
Genetic algorithm inversion for receiver functions with application to crust and uppermost mantle structure

Genetic algorithm (GA) inversion, a nonlin- ear global optimization technique, has been applied to determine crustal and uppermost mantle velocity struc- ture from teleseismic receiver functions. With a new vicinity of the receiver. The influence of the source can be largely eliminated by source equalization in which the radial component of motion is deconvolved with the vertical component to generate a receiver function (Langston,1979) which isolates conversions from P to $ generated at boundaries beneath the recording site. The receiver function waveform can be inverted in the
Wintertime high‐resolution features of sea surface temperature and chlorophyll‐a fields associated with oceanic fronts in the southern East China Sea

The southern East China Sea (ECS) and the sea north of Taiwan comprise an important transit area between the coastal waters of mainland China and the open water of the western North Pacific. Their wintertime dynamical features were examined using long‐term high‐resolution satellite‐derived sea surface temperature (SST) and chlorophyll‐a (Chl‐a) images. Along the Chinese coast, a cold‐water tongue with an SST of less than 15°C extended southwestwards from the ECS in December, intruded into the Taiwan Strait (TS) in January, and extended further southwestwards in February. Conforming with the cold SST development, the Chl‐a concentration starts to increase along the 50‐m isobath. However, in the sea north of Taiwan, the SST and the Chl‐a front between the shelf region and the eastern open ocean was semicircular in shape, left the shelf break and extended northeastwards. It was found that, along the semicircular Kuroshio front in the sea north of Taiwan, alternative cold and warm fronts appeared in the geographically fixed area in January and February. Based on the investigation of the snapshot SST images, their systematic appearance is attributed to an SST pattern similar to frontal eddies at the Kuroshio northern front. High concentrations of Chl‐a (>2.0 mg/m3) were found at the warm front and the offshore cold front patch.