Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Many highly contagious infectious diseases, such as COVID-19, monkeypox, chickenpox, influenza, etc., have seriously affected or currently are seriously affecting human health, economic activities, education, sports, and leisure. Many... more
Many highly contagious infectious diseases, such as COVID-19, monkeypox, chickenpox, influenza, etc., have seriously affected or currently are seriously affecting human health, economic activities, education, sports, and leisure. Many people will be infected or quarantined when an epidemic spreads in specific areas. These people whose activities must be restricted due to the epidemic are represented by targets in the article. Managing targets by using targeted areas is an effective option for slowing the spread. The Centers for Disease Control (CDC) usually determine management strategies by tracking targets in specific areas. A global navigation satellite system (GNSS) that can provide autonomous geospatial positioning of targets by using tiny electronic receivers can assist in recognition. The recognition of targets within a targeted area is a point-in-polygon (PtInPy) problem in computational geometry. Most previous methods used the method of identifying one target at a time, whi...
Research Interests:
Supergrid graphs are derived by computing stitch paths for computerized embroidery machines. In the past, we have studied the Hamiltonian-related properties of supergrid graphs and their subclasses of graphs. In this paper, we propose a... more
Supergrid graphs are derived by computing stitch paths for computerized embroidery machines. In the past, we have studied the Hamiltonian-related properties of supergrid graphs and their subclasses of graphs. In this paper, we propose a generalized graph class for supergrid graphs called extended supergrid graphs. Extended supergrid graphs include grid graphs, supergrid graphs, diagonal supergrid graphs, and triangular supergrid graphs as subclasses of graphs. In this paper, we study the problems of domination and independent domination on extended supergrid graphs. A dominating set of a graph is the subset of vertices on it, such that every vertex of the graph is in this set or adjacent to at least a vertex of this set. If any two vertices in a dominating set are not adjacent, this is called an independent dominating set. Domination and independent domination problems find a dominating set and an independent dominating set with the least number of vertices on a graph, respectively....
Research Interests:
The longest (s,t)-path problem on supergrid graphs is known to be NP-complete. However, the complexity of this problem on supergrid graphs with or without holes is still unknown.In the past, we presented linear-time algorithms for solving... more
The longest (s,t)-path problem on supergrid graphs is known to be NP-complete. However, the complexity of this problem on supergrid graphs with or without holes is still unknown.In the past, we presented linear-time algorithms for solving the longest (s,t)-path problem on L-shaped and C-shaped supergrid graphs, which form subclasses of supergrid graphs without holes. In this paper, we will determine the complexity of the longest (s,t)-path problem on O-shaped supergrid graphs, which form a subclass of supergrid graphs with holes. These graphs are rectangular supergrid graphs with rectangular holes. It is worth noting that O-shaped supergrid graphs contain L-shaped and C-shaped supergrid graphs as subgraphs, but there is no inclusion relationship between them. We will propose a linear-time algorithm to solve the longest (s,t)-path problem on O-shaped supergrid graphs. The longest (s,t)-paths of O-shaped supergrid graphs have applications in calculating the minimum trace when printing...
Research Interests:
A supergrid graph is a finite induced subgraph of the infinite graph associated with the two-dimensional supergrid. The supergrid graphs contain grid graphs and triangular grid graphs as subgraphs. The Hamiltonian cycle problem for grid... more
A supergrid graph is a finite induced subgraph of the infinite graph associated with the two-dimensional supergrid. The supergrid graphs contain grid graphs and triangular grid graphs as subgraphs. The Hamiltonian cycle problem for grid and triangular grid graphs was known to be NP-complete. In the past, we have shown that the Hamiltonian cycle problem for supergrid graphs is also NP-complete. The Hamiltonian cycle problem on supergrid graphs can be applied to control the stitching trace of computerized sewing machines. In this paper, we will study the Hamiltonian cycle property of linear-convex supergrid graphs which form a subclass of supergrid graphs. A connected graph is called k-connected if there are k vertex-disjoint paths between every pair of vertices, and is called locally connected if the neighbors of each vertex in it form a connected subgraph. In this paper, we first show that any 2-connected, linear-convex supergrid graph is locally connected. We then prove that any 2-...
Research Interests:
The hypercube is one of the most popular interconnection networks since it has simple structure and is easy to implement. The n-dimensional twisted cube, denoted by TQ_n, an important variation of the hypercube, possesses some properties... more
The hypercube is one of the most popular interconnection networks since it has simple structure and is easy to implement. The n-dimensional twisted cube, denoted by TQ_n, an important variation of the hypercube, possesses some properties superior to the hypercube. Recently, some interesting properties of TQ_n were investigated. In this paper, we construct two edge-disjoint Hamiltonian cycles in TQ_n for any odd integer n≥ 5. The presence of two edge-disjoint Hamiltonian cycles provides an advantage when implementing two algorithms that require a ring structure by allowing message traffic to be spread evenly across the twisted cube. Furthermore, we construct two equal node-disjoint cycles in TQ_n for any odd integer n≥ 3, in which these two cycles contain the same number of nodes and every node appears in one cycle exactly once. In other words, we decompose a twisted cube into two components with the same size such that each component contains a Hamiltonian cycle.
Research Interests:
A graph is called Hamiltonian connected if it contains a Hamiltonian path between any two distinct vertices. In the past, we proved the Hamiltonian path and cycle problems for general supergrid graphs to be NP-complete. However, they are... more
A graph is called Hamiltonian connected if it contains a Hamiltonian path between any two distinct vertices. In the past, we proved the Hamiltonian path and cycle problems for general supergrid graphs to be NP-complete. However, they are still open for solid supergrid graphs. In this paper, first we will verify the Hamiltonian cycle property of C-shaped supergrid graphs, which are a special case of solid supergrid graphs. Next, we show that C-shaped supergrid graphs are Hamiltonian connected except in a few conditions. For these excluding conditions of Hamiltonian connectivity, we compute their longest paths. Then, we design a linear-time algorithm to solve the longest path problem in these graphs. The Hamiltonian connectivity of C-shaped supergrid graphs can be applied to compute the optimal stitching trace of computer embroidery machines, and construct the minimum printing trace of 3D printers with a C-like component being printed.
Research Interests:
Supergrid graphs include grid graphs and triangular grid graphs as their subgraphs. The Hamiltonian path problem for general supergrid graphs is a well-known NP-complete problem. A graph is called Hamiltonian connected if there exists a... more
Supergrid graphs include grid graphs and triangular grid graphs as their subgraphs. The Hamiltonian path problem for general supergrid graphs is a well-known NP-complete problem. A graph is called Hamiltonian connected if there exists a Hamiltonian path between any two distinct vertices. In the past, we verified the Hamiltonian connectivity of some special supergrid graphs, including rectangular, triangular , parallelogram, trapezoid, and alphabet supergrid graphs, except few trivial conditions. In this paper, we will prove that every L-shaped supergrid graph always contains a Hamiltonian cycle except one trivial condition. We also present necessary and sufficient conditions for the existence of a Hamiltonian path between two given vertices in L-shaped supergrid graphs. The Hamiltonian connectivity of L-shaped supergrid graphs can be applied to compute the optimal stitching trace of computer embroidering machines while a varied-sized letter L is sewed into an object.
A Hamiltonian cycle in a graph G is a simple cycle in which each vertex of G appears exactly once. The Hamiltonian cycle problem involves testing whether a Hamiltonian cycle exists in a graph, and finds one if such a cycle does exist. It... more
A Hamiltonian cycle in a graph G is a simple cycle in which each vertex of G appears exactly once. The Hamiltonian cycle problem involves testing whether a Hamiltonian cycle exists in a graph, and finds one if such a cycle does exist. It is well known that the Hamiltonian cycle problem is one of the classic NP-complete problems on general graphs. Shih et al. solved the Hamiltonian cycle problem on circular-arc graphs in O(n 2 log n) time [36], where n is the number of vertices of the input graph. Whether there exists a more efficient algorithm for solving the Hamiltonian cycle problem on circular-arc graphs has been opened for a decade. In this paper, we present an O(∆n)-time algorithm to solve it, where ∆ denotes the maximum degree of the input graph.
Research Interests:
Let G = (V,E) be a graph with vertex set V and edge set E and let T be a subset of V. A terminal path cover PC of G with respect to T is a set of pairwise vertex-disjoint paths of G which cover the vertices of G such that all vertices in... more
Let G = (V,E) be a graph with vertex set V and edge set E and let T be a subset of V. A terminal path cover PC of G with respect to T is a set of pairwise vertex-disjoint paths of G which cover the vertices of G such that all vertices in T are end vertices of paths in PC. The terminal path cover problem is to find a terminal path cover of G of minimum cardinality with respect to T. The path cover problem is a special case of the terminal path cover problem with T be empty. In this paper, we show that the terminal path cover problem on trees can be solved in linear time.
Research Interests:
In this paper, we will introduce a novel family of interconnection network topologies, named disc-ring networks. Discring networks possess many desirable topological properties in building parallel machines, such as fixed degree, small... more
In this paper, we will introduce a novel family of interconnection network topologies, named disc-ring networks. Discring networks possess many desirable topological properties in building parallel machines, such as fixed degree, small diameter, hamiltonian decomposable, etc. We will study some topological properties of disc-ring networks. Furthermore, we also present an efficient routing algorithm for disc-ring networks. Keywords— Interconnection networks, discring network, hypercube, hamiltonian decomposable, diameter
Now, Internet of Things (IoT) brings people innovative experiences and applications through connectivity of numerous computing devices. In these applications, computing devices generate and exchange a large number of critical and... more
Now, Internet of Things (IoT) brings people innovative experiences and applications through connectivity of numerous computing devices. In these applications, computing devices generate and exchange a large number of critical and sensitive data. Typically, these computing devices are putted on some unprotected environments that make them to be attractive attack targets while easily suffering from a new kind of threat, called “side-channel attacks By side-channel attacks, an adversary could obtain partial information of secret values (or internal states) stored in these devices by observing execution timing or energy consumption. However, most adversary models of previous cryptographic schemes/protocols do not concern with such side-channel attacks. Indeed, leakage-resilient cryptography is a flexible solution for resisting to side-channel attacks. So far, little work focuses on the design of leakage-resilient certificate-based encryption (LR-CBE) schemes. In the article, we propose ...
Research Interests:
The longest path and Hamiltonian problems were known to be NP-complete. In spite of many applications of these problems, their complexities are still unknown for many classes of graphs, including supergrid graphs with holes and solid... more
The longest path and Hamiltonian problems were known to be NP-complete. In spite of many applications of these problems, their complexities are still unknown for many classes of graphs, including supergrid graphs with holes and solid supergrid graphs. In this paper, we will study the complexity of the longest (s, t)-path problem on O-shaped supergrid graphs. The longest (s, t)-path is a simple path from s to t with the largest number of visited vertices. An O-shaped supergrid graph is a rectangular supergrid graph with one rectangular hollow. We will propose a linear-time algorithm to find the longest (s, t)-path of O-shaped supergrid graphs. The longest (s, t)-paths of O-shaped supergrid graphs can be used to compute the smallest stitching path of computerized embroidery machine and 3D printer when a hollow object is printed.
In this paper, we first introduce a novel class of graphs, namely supergrid. Supergrid graphs include grid graphs and triangular grid graphs as their subgraphs. The Hamiltonian cycle and path problems for grid graphs and triangular grid... more
In this paper, we first introduce a novel class of graphs, namely supergrid. Supergrid graphs include grid graphs and triangular grid graphs as their subgraphs. The Hamiltonian cycle and path problems for grid graphs and triangular grid graphs were known to be NP-complete. However, they are unknown for supergrid graphs. The Hamiltonian cycle (path) problem on supergrid graphs can be applied to control the stitching trace of computerized sewing machines. In this paper, we will prove that the Hamiltonian cycle problem on supergrid graphs is NP- complete. It is easily derived from the Hamiltonian cycle result that the Hamiltonian path problem on supergrid graphs is also NP-complete. We then show that two subclasses of supergrid graphs, including rectangular (par- allelism) and alphabet, always contain Hamiltonian cycles.
Research Interests:
Supergrid graphs contain grid graphs and triangular grid graphs as their subgraphs. The Hamiltonian cycle and path problems for general supergrid graphs were known to be NP-complete. A graph is called Hamiltonian if it contains a... more
Supergrid graphs contain grid graphs and triangular grid graphs as their subgraphs. The Hamiltonian cycle and path problems for general supergrid graphs were known to be NP-complete. A graph is called Hamiltonian if it contains a Hamiltonian cycle, and is said to be Hamiltonian connected if there exists a Hamiltonian path between any two distinct vertices in it. In this paper, we first prove that every L-shaped supergrid graph always contains a Hamiltonian cycle except one trivial condition. We then verify the Hamiltonian connectivity of L-shaped supergrid graphs except few conditions. The Hamiltonicity and Hamiltonian connectivity of L-shaped supergrid graphs can be applied to compute the minimum trace of computerized embroidery machine and 3D printer when a L-like object is printed. Finally, we present a linear-time algorithm to compute the longest (s, t)-path of L-shaped supergrid graph given two distinct vertices s and t.
Research Interests:
Let $G=(V,E)$ be a graph without isolated vertices. A matching in $G$ is a set of independent edges in $G$. A perfect matching $M$ in $G$ is a matching such that every vertex of $G$ is incident to an edge of $M$. A set $S\subseteq V$ is a... more
Let $G=(V,E)$ be a graph without isolated vertices. A matching in $G$ is a set of independent edges in $G$. A perfect matching $M$ in $G$ is a matching such that every vertex of $G$ is incident to an edge of $M$. A set $S\subseteq V$ is a \textit{paired-dominating set} of $G$ if every vertex in $V-S$ is adjacent to some vertex in $S$ and if the subgraph $G[S]$ induced by $S$ contains at least one perfect matching. The paired-domination problem is to find a paired-dominating set of $G$ with minimum cardinality. A set $MPD\subseteq E$ is a \textit{matched-paired-dominating set} of $G$ if $MPD$ is a perfect matching of $G[S]$ induced by a paired-dominating set $S$ of $G$. Note that the paired-domination problem can be regard as finding a matched-paired-dominating set of $G$ with minimum cardinality. Let $\mathcal{R}$ be a subset of $V$, $MPD$ be a matched-paired-dominating set of $G$, and let $V(MPD)$ denote the set of vertices being incident to edges of $MPD$. A \textit{maximum matche...
Research Interests:
A Hamiltonian path (cycle) of a graph is a simple path (cycle) which visits each vertex of the graph exactly once. The Hamiltonian path (cycle) problem is to determine whether a graph contains a Hamiltonian path (cycle). A graph is called... more
A Hamiltonian path (cycle) of a graph is a simple path (cycle) which visits each vertex of the graph exactly once. The Hamiltonian path (cycle) problem is to determine whether a graph contains a Hamiltonian path (cycle). A graph is called Hamiltonian connected if there exists a Hamiltonian path between any two distinct vertices. Supergrid graphs were first introduced by us and include grid graphs and triangular grid graphs as their subgraphs. The Hamiltonian path (cycle) problem for grid graphs and triangular grid graphs was known to be NP-complete. Recently, we have proved that they are also NP-complete for supergrid graphs. These problems on supergrid graphs can be applied to control the stitching traces of computerized sewing machines. Very recently, we showed that rectangular supergrid graphs are Hamiltonian connected except two trivial forbidden conditions. In this paper, we will study the Hamiltonian connectivity of some shaped supergrid graphs, including triangular, parallelo...
Research Interests:
A Hamiltonian path (cycle) of a graph is a simple path (cycle) in which each vertex of the graph is visited exactly once. The Hamiltonian path (cycle) problem is to determine whether a graph contains a Hamiltonian path (cycle). A graph is... more
A Hamiltonian path (cycle) of a graph is a simple path (cycle) in which each vertex of the graph is visited exactly once. The Hamiltonian path (cycle) problem is to determine whether a graph contains a Hamiltonian path (cycle). A graph is called Hamiltonian if it contains a Hamiltonian cycle, and it is said to be Hamiltonian connected if there exists a Hamiltonian path between any two distinct vertices. Supergrid graphs were first introduced by us and include grid graphs and triangular grid graphs as their subgraphs. These problems on supergrid graphs can be applied to compute the stitching traces of computerized sewing machines. In the past, we have proved the Hamiltonian path (cycle) problem on supergrid graphs to be NP-complete. Recently, we showed that rectangular supergrid graphs are Hamiltonian connected except one trivial forbidden condition. In this paper, we will verify the Hamiltonicity and Hamiltonian connectivity of some shaped supergrid graphs, including triangular, par...
Let G =( V,E) be a graph without iso- lated vertices. A matching in G is a set of indepen- dent edges in G. A perfect matching M in G is a matching such that every vertex of G is incident to an edge of M. A set S ⊆ V is a... more
Let G =( V,E) be a graph without iso- lated vertices. A matching in G is a set of indepen- dent edges in G. A perfect matching M in G is a matching such that every vertex of G is incident to an edge of M. A set S ⊆ V is a paired-dominating set of G if every vertex not in S is adjacent to a vertex in S, and if the subgraph induced by S contains a perfect matching. The paired-domination problem is to find a paired-dominating set of G with minimum cardinality. The paired-domination problem on bi- partite graphs has been shown to be NP-complete. A bipartite graph G =( U,W,E) is convex if there exists an ordering of the vertices of W such that, for each u ∈ U, the neighbors of u are consecutive in W.I n
Research Interests:
The n-dimensional hypercube network Qn is one of the most popular interconnection networks since it has simple structure and is easy to implement. The n-dimensional augmented cube, denoted by AQn, an important variation of the hypercube,... more
The n-dimensional hypercube network Qn is one of the most popular interconnection networks since it has simple structure and is easy to implement. The n-dimensional augmented cube, denoted by AQn, an important variation of the hypercube, possesses several embedding properties that hypercubes and other variations do not possess. The advantages of AQn are that the diameter is only about half of the diameter of Qn and they are node-symmetric. Recently, some interesting properties of AQn were investigated. A graph G contains two- equal path partition if for any two distinct pairs of nodes (us; ut) and (vs; vt) of G, there exist two node-disjoint paths P and Q satisfying that (1) P joins us and ut, and Q joins vs and vt, (2) jPj = jQj, and (3) every node of G appears in one path exactly once. In this paper, we first use a simple recursive method to construct two edge-disjoint Hamiltonian cycles in AQn for any integer n > 3. We then show that the n-dimensional augmented cube AQn, with ...
Research Interests:
A connected domination set of a graph is a set D of vertices such that every vertex not in D is adjacent to at least one vertex in D, and the induced subgraph of D is connected. Given a circulararc graph G in arc model with n sorted arcs,... more
A connected domination set of a graph is a set D of vertices such that every vertex not in D is adjacent to at least one vertex in D, and the induced subgraph of D is connected. Given a circulararc graph G in arc model with n sorted arcs, we present an algorithm for finding a minimum connected domination set of G. Our algorithm runs in O(n) time and space.
The Hamiltonian path problem on general graphs is well-known to be NP-complete. In the past, we have proved it to be also NP-complete for supergrid graphs. A graph is called Hamiltonian connected if there exists a Hamiltonian path between... more
The Hamiltonian path problem on general graphs is well-known to be NP-complete. In the past, we have proved it to be also NP-complete for supergrid graphs. A graph is called Hamiltonian connected if there exists a Hamiltonian path between any two distinct vertices in it. Determining whether a supergrid graph is Hamiltonian connected is clear to be NPcomplete. Recently, we proved the Hamiltonian connectivity of some special supergrid graphs, including rectangular, triangular, parallelogram, and trapezoid. In this paper, we will study the Hamiltonian connectivity of alphabet supergrid graphs. There are 26 types of alphabet supergrid graphs in which every capital letter is represented by a type of alphabet supergrid graphs. We will prove L-, C-, F-, E-, N-, and Y-alphabet supergrid graphs to be Hamiltonian connected. The Hamiltonian connectivity of the other alphabet supergrid graphs can be verified similarly. The Hamiltonian connected property of alphabet supergrid graphs can be appli...
In this paper, we study a variant of the path cover problem, namely, the terminal path cover problem. Given a graph G and a subset T of vertices of G, a terminal path cover of G with respect to T is a set of pairwise vertex-disjoint paths... more
In this paper, we study a variant of the path cover problem, namely, the terminal path cover problem. Given a graph G and a subset T of vertices of G, a terminal path cover of G with respect to T is a set of pairwise vertex-disjoint paths PC that covers the vertices of G such that the vertices of T are all endpoints of the paths in PC. The terminal path cover problem is to find a terminal path cover of G of minimum cardinality; note that, if T is empty, the stated problem coincides with the classical path cover problem. We show that the terminal path cover problem can be solved in linear time on the class of block graphs. More precisely, we first establish a tree structural representation for the class of block graphs. Then, based on the tree structure, we present an algorithm which, for a block graph G on n vertices and m edges, computes a minimum terminal path cover of G in linear time, that is, in O(n+m) time. The proposed algorithm is simple and only requires linear space.
Research Interests:
The n-dimensional hypercube network Qn is one of the most popular interconnection networks since it has simple structure and is easy to implement. The n-dimensional augmented cube AQn, an important variation of the hypercube, possesses... more
The n-dimensional hypercube network Qn is one of the most popular interconnection networks since it has simple structure and is easy to implement. The n-dimensional augmented cube AQn, an important variation of the hypercube, possesses several embedding properties that hypercubes and other variations do not possess. The advantages of AQn are that the diameter is only about half of the diameter of Qn and it is node-symmetric. Recently, some interesting properties of AQn have been investigated in the literature. The presence of edge-disjoint Hamiltonian cycles provides an advantage when implementing algorithms that require a ring structure by allowing message traffic to be spread evenly across the interconnection network. A network G contains two-equal path cover and is called two-equal path coverable if for any two distinct pairs of nodes �µ s ,µ tand �υ s ,υ tof G, there exist two node-disjoint paths P and Q satisfying that (1) P joins µs and µt, and Q joins υs and υt, (2) |P | = |Q...
In this paper, we continue the study of the Hamiltonian and longest $(s, t)$-paths of supergrid graphs. The Hamiltonian $(s, t)$-path of a graph is a Hamiltonian path between any two given vertices $s$ and $t$ in the graph, and the... more
In this paper, we continue the study of the Hamiltonian and longest $(s, t)$-paths of supergrid graphs. The Hamiltonian $(s, t)$-path of a graph is a Hamiltonian path between any two given vertices $s$ and $t$ in the graph, and the longest $(s, t)$-path is a simple path with the maximum number of vertices from $s$ to $t$ in the graph. A graph holds Hamiltonian connected property if it contains a Hamiltonian $(s, t)$-path. These two problems are well-known NP-complete for general supergrid graphs. An $O$-shaped supergrid graph is a special kind of a rectangular grid graph with a rectangular hole. In this paper, we first prove the Hamiltonian connectivity of $O$-shaped supergrid graphs except few conditions. We then show that the longest $(s, t)$-path of an $O$-shaped supergrid graph can be computed in linear time. The Hamiltonian and longest $(s, t)$-paths of $O$-shaped supergrid graphs can be applied to compute the minimum trace of computerized embroidery machine and 3D printer when...
Research Interests:
Facebook is an online social media and social networking service, which is most popular in the world. Location-based Facebook check-in service is a hot topic. However, few studies are based on it as the research field. These studies... more
Facebook is an online social media and social networking service, which is most popular in the world. Location-based Facebook check-in service is a hot topic. However, few studies are based on it as the research field. These studies always are based on Foursquare as the research field. One of the major reasons is that Facebook platform only allows limited data access. In this study, we present a method that can efficiently analyze the hot spot areas of Facebook places and take Taipei City in Taiwan for Example.
Research Interests:
Supergrid graphs are first introduced by us and their structures are derived from grid and triangular-grid graphs. The Hamiltonian path problem on general supergrid graphs is a NP-complete problem. A graph is said to be Hamiltonian... more
Supergrid graphs are first introduced by us and their structures are derived from grid and triangular-grid graphs. The Hamiltonian path problem on general supergrid graphs is a NP-complete problem. A graph is said to be Hamiltonian connected if a Hamiltonian path between any two nodes in it does exist. In the past, deciding whether or not a general supergrid graph contains a Hamiltonian path has been proved to be NP-complete. Very recently, we verified the Hamiltonian connectivity of some special supergrid graphs, including triangular, parallelogram, trapezoid, and rectangular supergrid graphs, except few conditions. In this paper, the Hamiltonian connectivity of alphabet supergrid graphs will be verifed. There are 26 types of alphabet supergrid graphs in which every capital letter is represented by a type of alphabet supergrid graphs. We will provide constructive proofs to verify the Hamiltonian connectivity of L-, F-, C-, and E-alphabet supergrid graphs. The results can be used to verify the Hamiltonian connectivity of other alphabet supergrid graphs with similar structure, such as G-, H-, J-, I-, O, P-, T-, S-, and U-alphabet supergrid graphs. The application of the Hamiltonian connectivity of alphabet supergrid graphs can be to compute the minimum stitching track of computer embroidery machines while a string is sewed into an object.
Research Interests:
Research Interests:
Research Interests:
Applying Internet-of-Things (IoT) technologies in agriculture not only can reduce the man efforts but also improve the productivity and the efficiency. Through the IoT technologies, one can collect various data like luminosity,... more
Applying Internet-of-Things (IoT) technologies in agriculture not only can reduce the man efforts but also improve the productivity and the efficiency. Through the IoT technologies, one can collect various data like luminosity, temperature, humidity, PH value, etc to analyze and control the facilities. In this study, we focus on exploring the application of the infra-red data on agriculture IoT systems, in addition to the design of our green-house IoT system. Through the infra-red data, we can analyze various biological data of the plants and the fruits. Based on several low-cost devices (like Raspberry pi, NoIR camera, thermal camera, various sensors), some open source platforms, and the Splunk software, we design and build an green-house IoT system that not only collects various environment data but also analyze the biological data of plants via the infra-red data. Some preliminary experiments and analysis are given in this paper. The results show that low-cost infra-red devices could have a great potential contribution to improving agriculture practice.
Lightweight Message Queue Telemetry Transport (MQTT) gains its popularity in many Inter of things implementations. However, MQTT is efficient at the cost of weak security support. Moreover, under large connection requests, MQTT brokers... more
Lightweight Message Queue Telemetry Transport (MQTT) gains its popularity in many Inter of things implementations. However, MQTT is efficient at the cost of weak security support. Moreover, under large connection requests, MQTT brokers would become the bottlenecks and degrade the whole system performance. In this paper, we propose the first Hierarchical MQTT framework with Edge Computation (HMQTTEC). In this framework, brokers are organized in a hierarchical relation, according to their geographical properties or application requirements. The brokers arranged in lower layers handle the data sharing in their domains, perform edge computations (like summation, averaging, etc) on domain data, and report the processed data to their parental brokers. We implement a prototype system for the PM2.5 pollution monitoring application to access the performance of the design. The results and the analysis show the effectiveness and the efficiency of our design.
Research Interests: Computer Science and IEEE
Infectious diseases, such as COVID-19, SARS, MERS, etc., have seriously endangered human safety, economy, and education. During the spread of epidemics, restricting the range of activities of personnel is one of the options for the... more
Infectious diseases, such as COVID-19, SARS, MERS, etc., have seriously endangered human safety, economy, and education. During the spread of epidemics, restricting the range of activities of personnel is one of the options for the prevention and treatment of infectious diseases. A global navigation satellite system (GNSS), it can provide accurate coordinates of latitude and longitude to targets with GNSS receivers. However, it is not common to use GNSS coordinates to represent positions in social life. For epidemic management, it is important to know the locations (and addresses) of targets, especially in social life. When there are many targets, it is not easy to efficiently map these coordinates to locations. Therefore, we propose a GNSS-based crowd-sensing strategy for specific geographical areas that can be used to calculate how many targets are in specific geographical areas or whether a target is in a specific area. This strategy is based on the coordinates of latitude and lo...
Research Interests:
ABSTRACT The major problem of SVMs is the dependence of the nonlinear separating surface on the entire dataset which creates unwieldy storage problems. This paper proposes a novel design algo- rithm, called the extractive support vector... more
ABSTRACT The major problem of SVMs is the dependence of the nonlinear separating surface on the entire dataset which creates unwieldy storage problems. This paper proposes a novel design algo- rithm, called the extractive support vector algorithm, whi ch provides improved learning speed and a vastly improved performance. Instead of learning and training with all input patterns, the proposed algorithm selects support vectors from the input patterns a nd uses these support vectors as the train- ing patterns. Experimental results reveal that our propose d algorithm provides near optimal solutions and outperforms the existing design algorithms. In addition, a significant framework which is based on extractive support vector algorithm is proposed for image restoration. In the framework, input patterns are classified by three filters: weighted order stat istics filter, alpha-trimmed mean filter and identity filter. Our proposed filter can achieve three object ives: noise attenuation, chromaticity reten- tion, and preservation of edges and details. Extensive simulation results illustrate that our proposed filter not only achieves these three objectives but also poss esses robust and adaptive capabilities, and outperforms other proposed filtering techniques.
Research Interests:
Research Interests:
Research Interests:
A supergrid graph is a finite induced subgraph of the infinite graph associated with the two-dimensional supergrid. The supergrid graphs contain grid graphs and triangular grid graphs as subgraphs. The Hamiltonian cycle problem for grid... more
A supergrid graph is a finite induced subgraph of the infinite graph associated with the two-dimensional supergrid. The supergrid graphs contain grid graphs and triangular grid graphs as subgraphs. The Hamiltonian cycle problem for grid and triangular grid graphs was known to be NP-complete. Recently, we have proved the Hamiltonian cycle problem for supergrid graphs to be NP-complete. The Hamiltonian cycle problem on supergrid graphs can be applied to control the stitching trace of computerized sewing machines. In this paper, we will study the Hamiltonian cycle property of linear-convex supergrid graphs which form a subclass of supergrid graphs. A connected graph is called k-connected if there are k vertex-disjoint paths between every pair of vertices, and is called locally connected if the neighbors of each vertex in it form a connected subgraph. In this paper, we first show that any 2-connected, linear-convex supergrid graph is locally connected. We then prove that any 2-connected, linear-convex supergrid graph contains a Hamiltonian cycle.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
The major problem of SVMs is the dependence of the nonlinear separating surface on the entire dataset which creates unwieldy storage problems. This paper proposes a novel design algo- rithm, called the extractive support vector algorithm,... more
The major problem of SVMs is the dependence of the nonlinear separating surface on the entire dataset which creates unwieldy storage problems. This paper proposes a novel design algo- rithm, called the extractive support vector algorithm, whi ch provides improved learning speed and a vastly improved performance. Instead of learning and training with all input patterns, the proposed algorithm selects support vectors from the input patterns a nd uses these support vectors as the train- ing patterns. Experimental results reveal that our propose d algorithm provides near optimal solutions and outperforms the existing design algorithms. In addition, a significant framework which is based on extractive support vector algorithm is proposed for image restoration. In the framework, input patterns are classified by three filters: weighted order stat istics filter, alpha-trimmed mean filter and identity filter. Our proposed filter can achieve three object ives: noise attenuation, chromaticity ...
Research Interests:
The presence of edge-disjoint Hamiltonian cycles provides an advantage when implementing algorithms that require a ring structure by allowing message traffic to be spread evenly across the network. Edge-disjoint Hamiltonian cycles also... more
The presence of edge-disjoint Hamiltonian cycles provides an advantage when implementing algorithms that require a ring structure by allowing message traffic to be spread evenly across the network. Edge-disjoint Hamiltonian cycles also provide the edge-fault tolerant hamiltonicity of an interconnection network. In this paper, we first study the property of edge-disjoint Hamiltonian cycles in transposition networks which form a subclass of Cayley graphs. The transposition networks include other famous network topologies as their subgraphs, such as meshes, hypercubes, star graphs, and bubble-sort graphs. We first give a novel decomposition of transposition networks. Using the proposed decomposition, we show that -dimensional transposition network with contains four edge-disjoint Hamiltonian cycles. By using the similar approach, we present a linear time algorithm to construct two edge-disjoint Hamiltonian cycles on crossed cubes which is a variation of hypercubes. The proposed approac...
Research Interests:
A supergrid graph is a finite induced subgraph of the infinite graph associated with the two-dimensional supergrid. The supergrid graphs contain grid graphs and triangular grid graphs as subgraphs. The Hamiltonian cycle problem for grid... more
A supergrid graph is a finite induced subgraph of the infinite graph associated with the two-dimensional supergrid. The supergrid graphs contain grid graphs and triangular grid graphs as subgraphs. The Hamiltonian cycle problem for grid and triangular grid graphs was known to be NP-complete. In the past, we have shown that the Hamiltonian cycle problem for supergrid graphs is also NP-complete. The Hamiltonian cycle problem on supergrid graphs can be applied to control the stitching trace of computerized sewing machines. In this paper, we will study the Hamiltonian cycle property of linear-convex supergrid graphs which form a subclass of supergrid graphs. A connected graph is called $k$-connected if there are $k$ vertex-disjoint paths between every pair of vertices, and is called locally connected if the neighbors of each vertex in it form a connected subgraph. In this paper, we first show that any 2-connected, linear-convex supergrid graph is locally connected. We then prove that an...
Research Interests:
A certifying algorithm for a problem is an algorithm that provides a certificate with each answer that it produces. The certificate is a piece of evidence that proves the answer has no compromised by a bug in the implementation. A... more
A certifying algorithm for a problem is an algorithm that provides a certificate with each answer that it produces. The certificate is a piece of evidence that proves the answer has no compromised by a bug in the implementation. A Hamiltonian cycle in a graph is a simple cycle in which each vertex of the graph appears exactly once. The Hamiltonian cycle problem is to test whether a graph has a Hamiltonian cycle. A path cover of a graph is a family of vertex-disjoint paths that covers all vertices of the graph. The path cover problem is to find a path cover of a graph with minimum cardinality. The scattering number of a noncomplete connected graph G = (V,E) is defined by s(G) = max {ω(G − S) − |S|: S ⊆ V and w</font >(G-</font >S)\geqslant 1}\omega(G-S)\geqslant 1\}, in which ω(G − S) denotes the number of components of the graph G − S. The scattering number problem is to determine the scattering number of a graph. A recognition problem of graphs is to decide whether a given input graph has a certain property. To the best of our knowledge, most published certifying algorithms are to solve the recognition problems for special classes of graphs. This paper presents O(n)-time certifying algorithms for the above three problems, including Hamiltonian cycle problem, path cover problem, and scattering number problem, on interval graphs given a set of n intervals with endpoints sorted. The certificates provided by our algorithms can be authenticated in O(n) time.