Papers by Saluka Kodituwakku
An efficient planar incremental convex hull algorithm to find the edges of the boundary polygon of the convex hull of a set of points
Ceylon Journal of Science
The definition of the convex hull of a set of points is the smallest convex set containing all th... more The definition of the convex hull of a set of points is the smallest convex set containing all the points. Many algorithms have been proposed with the worst case time complexity is equal to O (n log n). It has been proved that the lower bound of time complexity for construction of the convex hull is O (n log n). However, these algorithms are static and require all points at the start. Suppose that points reach sequentially one after one and the convex hull needs to be maintained at each insertion of a point. The convex hull should be constructed from the scratch to handle each point insertion if a static convex hull algorithm was used. This process consumes O (n log n) time and therefore it is inefficient. An incremental convex hull algorithm can maintain the convex hull at each insertion performing a trivial modification to the existing convex hull without constructing the convex hull from the scratch. The optimal time complexity for insertion of a point in existing incremental convex hull algorithms is O (n). A new incremental convex hull algorithm with O (h2) time complexity is proposed in this paper. Note that h represents the number of vertices of the convex hull. A set of line segments is used to represent the convex hull. Some of the existing line segments may be deactivated instead of deleting upon the successive growth of the convex hull. Thus, the computational cost is reduced. The proposed algorithm is faster than the existing algorithms when h < SQRT (n) and the concept can be extended to three dimensions.
A novel and efficient approach for line segment clipping against a convex polygon
Ruhuna Journal of Science
This paper proposes a new line clipping algorithm against a convex polygon with O (N) time comple... more This paper proposes a new line clipping algorithm against a convex polygon with O (N) time complexity. The line segment is pruned against each extended edge of the polygon as the first step of the proposed algorithm. Then, the pruning process gives accurate outcomes for completely inside and partially inside line segments only. It could be observed that the endpoints of completely outside line segments coincide after the pruning process. The algorithm was developed based on this observation. The proposed algorithm was compared against the four existing algorithms both theoretically and experimentally. The proposed algorithm is faster than Cyrus Beck algorithm and it is slower than ECB, Rappaport, and Skala algorithms.
PeerJ Computer Science, 2016
It is a well-known fact that some criminals follow perpetual methods of operations known as modi ... more It is a well-known fact that some criminals follow perpetual methods of operations known as modi operandi. Modus operandi is a commonly used term to describe the habits in committing crimes. These modi operandi are used in relating criminals to crimes for which the suspects have not yet been recognized. This paper presents the design, implementation and evaluation of a new method to find connections between crimes and criminals using modi operandi. The method involves generating a feature matrix for a particular criminal based on the flow of events of his/her previous convictions. Then, based on the feature matrix, two representative modi operandi are generated: complete modus operandi and dynamic modus operandi. These two representative modi operandi are compared with the flow of events of the crime at hand, in order to generate two other outputs: completeness probability (CP) and deviation probability (DP). CP and DP are used as inputs to a fuzzy inference system to generate a sco...
Fuzzy and ANN Control System for Backing up a Truck and Trailer
International Journal of Computer Applications, 2015
Understanding community structure helps to interpret the role of actors in a social network. Acto... more Understanding community structure helps to interpret the role of actors in a social network. Actor has close ties to actors within a community than actors outside of its community. Community structure reveals important information such as central members in communities and bridges members who connect communities. Clustering algorithms like hierarchical clustering, affinity propagation, modularity and spectral graph clustering had been applied in social network clustering to identify community structures in it. This study proposes a novel method for distance measurement between nodes and centroids. Distance is measured based on the shortest path length and number of common nearest neighbors with one path length. This measure, "Proportional closeness" is used to assign nodes to the closest centroid. A fuzzy system is also applied to find the closest centroid to a node when similar proportional closeness values are present for multiple centroids. The method has been applied to two artificial networks and one real world network data to test its accuracy on membership identification. The results revealed that the method successfully assigns members to its nearest centroid and leave neutral members aside without assigning to any centroid.
Use of J48 Classification Algorithm for Nearest Police Station Detection
ABSTRACT GIS (Geographic Information System) has become one of the widely used technologies in th... more ABSTRACT GIS (Geographic Information System) has become one of the widely used technologies in the modern world. GPS (Geographic Positioning Systems) facilitates the users to locate current ground position on digital map; accurately and easily. However GPS and GIS itself are not sufficient to produce useful information. Adopting computer based modern analysis and prediction techniques in to GPS and GIS systems will enable us to generate more useful information. This paper presents an effective integration of J48 classification algorithm in predicting the nearest police station to a given coordinate position on a digital map. This functionality is automated using the OpenLayers API (Application and Programming Interface) and Google maps enhancing the decision support up to a very high extent. This automated GIS environment enabled the integration of the nearest police station detection (NPSD) tool to the system in an easy manner. In NPSD tool, J48 classification algorithm has been trained classifying the geographical coordinates (longitudes and latitudes) to a set of predefined classes that are police stations distributed on part of a map of interest. 400 coordinate points were classified under one police station under the algorithm training process. This allows classifying an unknown coordinate point on a map to the nearest police station. This is very useful for police officers to find the nearest police station in an emergency situation. Whenever a coordinate point location is provided, through GPS or just by triggering the click event on the map, that point will be directed to the system as a GET request and filtered through the well trained J48 algorithm for finding the nearest police station. After the Nearest police station is identified, it will then be routed to the user in order to be displayed on the devise. Application of J48 algorithm in identifying the nearest police station recorded 90% accuracy level.
GIS-based Hotspot Detection in Crime Analysis
ABSTRACT It is observed that law enforcement authorities all around the world lack a good and eff... more ABSTRACT It is observed that law enforcement authorities all around the world lack a good and efficient crime analysis system facilitated by the new advancement of information technology. The globalization and increasing complexity of crime patterns have made the analysis of crime date even difficult. Sri Lanka&#39;s police too have been dealing with these difficulties for a long period of time. This paper discuses an efficient method of utilizing geographical hotspot detection technology to help investigation and prevention of crimes. The proposed GIS (Geographical Information System) bases system allows users to locate crime-hotspots and take necessary measures to prevent crime incidents associated with them. High rate of population growth and use of advance technology have resulted a higher magnitude of crime incidents which emphasize the need of efficient and effective crime analysis procedures. With the advancement of new technology, crime activities are becoming increasingly intelligence backed and hard to trace. Majority of crimes nowadays tend to operate over a long period of time, making them even harder to analyze and predict. Therefore, it is obvious that conventional manual procedures of crime investigation are becoming no longer reliable and not efficient enough to deal with these new trends of criminal activities. This is one of the main problems faced by law enforcement authorities nowadays. Inefficiency and the tediousness of this task make the confidence in tracking the exact criminal low. Moreover, the current system does not make use of many newer crime analysis techniques such as crime trend analysis, real-time crime outbreak detection, crime pattern identification, hotspot detection, crime association mining etc. This is mainly because of the magnitude of the dataset to deal with allows no time for such procedures to be operated on it manually. The proposed automated web based intelligent crime analysis system (SL-SecureNet) facilitated by GIS comprised of an affluent set of data mining tools would literally annihilate the flaws associated with the above mentioned manual procedure. Hotspot detection plays one of the major roles in this system. The data about the area to be investigated is first fed to the clustering algorithm as input. The Euclidian distance among all the data points with respect to each other is measured by the algorithm based on the input. Then the data points are clustered, with appropriate points in each cluster, using the nearest neighbor concept and the calculated Euclidean distances. Finally the coordinates of the center point of each cluster is worked out and the number of crime points inside each of the cluster is returned. Each cluster is denoted by density of coloration of it according to the magnitude of the cluster. These hotspots are then displayed on the base maps using vector layers. The system was tested in the Sri Lankan context. The test results indicated that the system is efficient and reliable.
Data Access Control in Virtual Organizations-Role-Based Access Control Patterns
Intelligent Crime Investigation Using Data Mining Techniques
ABSTRACT Many police departments in all over the world lack of fast crime investigation systems. ... more ABSTRACT Many police departments in all over the world lack of fast crime investigation systems. The amount of crimes recorded each year is very high. For example, Sri Lankan police department records around 55,000 grave crimes each year. Not only that, the geographical diversity and the modi operandi diversity of these crime data is very high and the amount of deceptive incidents recorded will also be very high. Due to these problems, recording, investigation, analysis and maintenance of crime data have become a tedious task. Therefore, the necessity of a good automated crime analysis system arises in many police departments in all over the world. This paper proposes a good and efficient automated intelligent crime investigation system for the Sri Lankan police department. The proposed system is expected to be developed based on data mining and GIS technologies.
High Speed Motion Tracking for Weightlifting based on Correlation Coefficient Template Matching
ABSTRACT Tracking of motion in weightlifting is a challenging task. This paper presents a method ... more ABSTRACT Tracking of motion in weightlifting is a challenging task. This paper presents a method for tracking Weightlifting bar movement of an athlete. The proposed method uses three different template creation techniques for tracking and applies Wilcoxon Signed rank test to evaluate the results. The method was tested with normally captured data (30fps) and data captured in slow motion (100fps) separately. For the normally captured data, combined dynamic templates method has the highest accuracy of 95% in tracking the trajectory. For slow motion data Wilcoxon Signed Rank generated equal results for all three template creation methods.
Data Access Control in Virtual Organisations
Digital Enterprise Challenges, 2002
SL-SecureNet: Intelligent Policing Using Data Mining Techniques
International Journal of …
... Computer 37 (4):50-56. MA Pathum Chamikara is working as a research assistant at the Post Gra... more ... Computer 37 (4):50-56. MA Pathum Chamikara is working as a research assistant at the Post Graduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka. He received his BSc (Special) degree in Computer Science, University of Peradeniya, Sri Lanka (2010). ...
Pattern categories: a mathematical approach for organizing design patterns
Proceedings of the 2002 conference on …, 2003
Page 1. Pattern Categories: A Mathematical Approach for Organizing Design Patterns Saluka R. Kodi... more Page 1. Pattern Categories: A Mathematical Approach for Organizing Design Patterns Saluka R. Kodituwakku Peter Bertok Department of Computer Science, RMIT University, Australia, Email: (sakoditu,pbertok)@cs.rmit.edu.au Abstract ...
This paper presents a new genetic algorithm approach to solve the shortest path problem for road ... more This paper presents a new genetic algorithm approach to solve the shortest path problem for road maps. This is based on the analogy of finding the shortest possible distance between two towns or cities in a graph or a map with potential connection, which means that the path distances are always positive. Typically this is represented by a graph with each node representing a city and each edge being a path between two cities and there exist some traditional algorithms that produce solutions for the problem. A new method is found to solve the shortest path problem using GAs. The algorithm has been tested for a road map containing more than 125 cities and the experimental results guarantee to provide acceptably good solutions for the given search space.
This paper presents a literature review of current routing protocols used in mobile ad hoc networ... more This paper presents a literature review of current routing protocols used in mobile ad hoc network (MANET). Routing is a most challenging issue in ad hoc network since nodes are mobile and the dynamic nature of the topology. Routing metrics such as shortest path, QoS, power consumption and position location are being used to reduce discovery time and also message update cost. This paper presents a thorough overview of some of the QoS routing protocols along with their strengths and weaknesses. A comparative study of the reactive, proactive and hybrid QoS routing protocols is done and in addition, the current issues and future challenges that are involved in this exciting area of research are also included.
This paper presents a literature review of current routing protocols used in mobile ad hoc networ... more This paper presents a literature review of current routing protocols used in mobile ad hoc network (MANET). Routing is a most challenging issue in ad hoc network since nodes are mobile and the dynamic nature of the topology. Routing metrics such as shortest path, QoS, power consumption and position location are being used to reduce discovery time and also message update cost. This paper presents a thorough overview of some of the QoS routing protocols along with their strengths and weaknesses. A comparative study of the reactive, proactive and hybrid QoS routing protocols is done and in addition, the current issues and future challenges that are involved in this exciting area of research are also included.
Content based Image Retrieval (CBIR) allows automatically extracting target images according to o... more Content based Image Retrieval (CBIR) allows automatically extracting target images according to objective visual contents of the image itself. Representation of visual features and similarity match are important issues in CBIR. Colour and texture features are important properties in CBIR systems. In this paper, a combined feature descriptor for CBIR is proposed to enhance the retrieval performance for CBIR. This method is developed by exploiting the wavelets and colour histogram moments. First, Haar wavelet is used to decompose colour images into wavelet coefficients. Then image feature extraction and similarity matching are performed by means of histogram moments. Ten categories of colour images are used to test the proposed technique. Experiment results show significant improvement of retrieval efficiency as compared to that of histogram moments as well as 2D Discrete Wavelet Transform.
A new public key cryptosystem is proposed, together with signature capabilities. This system base... more A new public key cryptosystem is proposed, together with signature capabilities. This system based on In-vertibility of finite automata. The security of the system rests on difficulty of finding inverse automatas and difficulty of factoring matrix polynomi a1 over Galois field GF(2). I Introduction In 1976, Diffie and Hellman[2] introduced the concept of public key cryptosystems. The basic idea of the Public key cryptosystem is that every user has one public encryption algorithm E and one secret decryption algorithm D. These algorithms are satisfies the following conditions. (1). Dk is the inverse of Ek. That is Dk(Ek(X)) = X. (2). Dk and are easy to compute. (3). For almost every k in K , D k is computationally infeasible to determine from E k. Since then several public key cryptosystems were proposed ,mainly it can be divided into three groups. One is trapdoor knapsacks cryptosystems and its variances , this cryptosystem is based on an NP-complete combinatorial problem[3]. The second one is RSA, that is depends on the difficulty of factoring large inte-gers[l]. The third group is Mczliece cryptosystems, this system is based on algebric cording theory[l5]. This paper present a cryptosystem rely on difficulty of inversion of a nonlinear finite autom ata and of factoring matrix polynomials over Galois Field GF(2). Section I1 gives the software implementation of the proposed system and section I11 gives some properties of the system. Section IV contains conclusion and references. I1 Software implementation of the system In order to implement software, the following finite automata are constructed over GF(2) with m-dimensional input output alphabets. (1). (ha, ko) order memory linear finite automaton MO = < X, U, Y k o x X h o , 60, XO > defined by k n hn 3 =l j =O (2). Weakly inverse of &IO is constructed with delay TO. That is a (TO + ko, ho) order memory linear finite automaton M$ =< Y , X , Xho x Y ' o + ~ ~ , 5$, > defined by ho ' 0 f k 0. (i) =-p i Z (i-j) + c Aj*y(i-j) , i = 0,1, 3. . 3=1 3 =O (3). hl order nonlinear memory input finite automata M 1 =< X , X , X h l , 51, A1 > defined by h , h ,-1 3 =O j = 1 (4). Weakly inverse of M1 is constructed with delay 71. That is a (TI, h l) order nonlinear memory input finite automata M: =< X , X , X r l f h l , bf, Ay > defined by hi hl-1 .(.) =-p;+,,+ F;*=(~-l)+.l-l)+ e 3 D*-.'(r-,), E = 0,1, .. 1=1 3'1 3 = 0 (5). The superposition of MI and MO. That is a (hl + ho, ko) order nonlinear memory finite automaton C'(M1, MO) defined by k n h n + h > h n + h i-1 (6). Denote T = maximum(TO ,TI $ 0) and then choose following arbitrary values and states Y-l,s, Y-Z , S , .'.'.... , Y-7-71,s in y, 0-7803-291 6-3 07. 08.1
This paper presents a collection of object-oriented design patterns structured to form a pattern ... more This paper presents a collection of object-oriented design patterns structured to form a pattern language for Role Based Access Control (RBAC). A hypothetic banking application is used to describe how these patterns support the design and implementation of RBAC models.
The main objective of this research is to present a new role based access control (FRBAC) model f... more The main objective of this research is to present a new role based access control (FRBAC) model for database security that provides additional level of security checks by extending an existing RBAC model. The proposed model allows modeling of vague organizational security policies or the access control rules in Multipolicy paradigm, using fuzzy parameters. Also in contrast to current notion of RBAC, it provides both static and dynamic permission assignment. The model determines whether a request to perform an operation on the database, granted or denied according to the sensitivity level of the data being affected by the request, the type of request being made, and the need to write or read on those resources, of the user making the request. Typically, such information is very difficult to determine precisely, since it depends on other attributes that are themselves imprecise or only partially known. The proposed model addresses this by using a fuzzy approach. The paper presents an algorithm for generating such fuzzy information based on their dependent attributes. The method is based on fuzzy linguistic variables and some straightforward multi-objective fuzzy decision-making.
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Papers by Saluka Kodituwakku