Modern robotic exploratory strategies assume multi-agent cooperation that raises a need for an effective exchange of acquired scans of the environment with the absence of a reliable global positioning system. In such situations, agents compare the scans of the outside world to determine if they overlap in some region, and if they do so, they determine the right matching between them. The process of matching multiple point-cloud scans is called point-cloud registration. Using the existing point-cloud registration approaches, a good match between any two-point-clouds is achieved if and only if there exists a large overlap between them, however, this limits the advantage of using multiple robots, for instance, for time-effective 3D mapping. Hence, a point-cloud registration approach is highly desirable if it can work with low overlapping scans. This work proposes a novel solution for the point-cloud registration problem with a very low overlapping area between the two scans. In doing so, no initial relative positions of the point-clouds are assumed. Most of the state-of-the-art point-cloud registration approaches iteratively match keypoints in the scans, which is computationally expensive. In contrast to the traditional approaches, a more efficient line-features-based point-cloud registration approach is proposed in this work. This approach, besides reducing the computational cost, avoids the problem of high false-positive rate of existing keypoint detection algorithms, which becomes especially significant in low overlapping point-cloud registration. The effectiveness of the proposed approach is demonstrated with the help of experiments.

Location has always been a primary concern for business startups to be successful. Therefore, much research has focused on the problem of identification of an ideal business site for a new business. The process of ideal business site selection is complex and depends on a number of criteria or factors. Since the ultimate goal of all businesses is to increase customer footprints and to thus increase sales, criteria including traffic accessibility, visibility, ease of access, vehicle parking, customers availability, etc. play important roles. In other words, we can say that optimal business site selection is a multi-criteria decision-making (MCDM) problem. MCDM is used to identify an optimal solution or decision out of many alternatives by utilizing a number of criteria. In mathematics, there exist a number of structured techniques for organizing and analyzing complex decisions, for instance, AHP, ANP, TOPSIS, etc. In this work, we present a hybrid of two such techniques to solve the MCDM problem for an optimal business site selection given a set of candidate sites. The proposed approach is based on the AHP (Analytic Hierarchy Process) and TOPSIS (The Technique for Order of Preference by Similarity to Ideal Solution) approaches. The reason for using the proposed hybrid approach is multi-fold. The hybrid approach reduces the computational complexity and require less manual effort, thus improving the efficiency and accuracy of the proposed approach. Given a set of candidate locations for a new business, the proposed approach ranks the candidates. Thus, the candidate locations with higher ranks are identified as suitable or ideal. The approach comes up with the ranking of all of the candidate locations, thus giving business managers room to make calculated decisions. To show the effectiveness of the proposed approach, a detailed step-by-step case study is given to identify an ideal location in New York City for a new gas station. Furthermore, an experimental evaluation is also presented using a number of real New York City datasets.

This era is witnessing an exponential growth in spatial data due to the increase in GPS-enabled devices. Spatial data can be of extreme use to commercial businesses, governments and NGOs if processed timely. Spatial data is voluminous and is usually generated as a continuous data stream, for instance, vehicles tracking data, mobile location data, etc. To process such a huge data streams, highly scalable systems are needed. Apache Spark Streaming, Apache Flink, and Apache Samza are among the state-of-the-art scalable stream processing platforms; however, they lack spatial objects, indexes, and queries support. Besides them, other scalable spatial data processing platforms including GeoSpark, Spatial Hadoop do not support streaming workloads and can only handle static or batch data. To fill this gap, we present GeoFlink which extends Apache Flink to support spatial objects, indexes and continuous queries over spatial data streams. A grid-based index is introduced to support efficient spatial query processing and effective data distribution across distributed cluster nodes. GeoFlink supports spatial range, spatial $k$ NN and spatial join queries on Point, LineString, Polygon, MultiPoint, MultiLineString, and MultiPolygon spatial objects. Besides, GeoFlink supports data streams in GeoJSON, WKT, and CSV data formats. A detailed experimental study on real and synthetic spatial data streams proves that GeoFlink achieves significantly higher query throughput than the existing state-of-the-art streaming platforms.

Explosive increase of real-time data sources, so-called "data streams" (or just "steams") and increasing demands for real-time analysis over streams give rise to realtime analysis over streams. However, developing tailor-made systems for such applications is not always desirable due to high developing costs and long developing periods. To cope with this problem, this paper proposes a novel architecture for online analytical processing (OLAP) over streams exploiting off-the-shelf stream processing engine (SPE) combined with OLAP engine. It allows users to perform OLAP analysis over streams for the latest time period, called Interval of Interest (Iol). The system in the meantime processes multiple continuous query language (CQL) queries corresponding to different aggregation levels in cube lattice. To cover arbitrary aggregation levels using limited system's memory, we propose to partially deploy CQL queries for those with higher reference frequencies, whereas the results are dynamically calculated using existing aggregation results with the help of OLAP engine. For optimal CQL query deployment, we propose a cost-based optimization method that maximizes the performance. The experimental results show that the proposed architecture is feasible enough to realize stream OLAP by combining an SPE and an OLAP engine. Also, the proposed system significantly outperforms other comparative methods by generating optimized query deployment plans.