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Wireless sensor networks promise a new paradigm for gathering data via collaboration among sensors spreading over a large geometrical region. Many real-time applications impose stringent delay requirements and ask for time-efficient schedules of data aggregations in which sensed data at sensors are combined at intermediate sensors along the way towards the(More)
Given n terminals in the Euclidean plane and a positive constant, find a Steiner tree interconnecting all terminals with the minimum number of Steiner points such that the Euclidean length of each edge is no more than the given positive constant. This problem is NP-hard with applications in VLSI design, WDM optical networks and wireless communications. In(More)
This paper discusses quality-of-service (QoS) multicast in wavelength-division multiplexing (WDM) networks. Given a set of QoS multicast requests, we are to find a set of cost suboptimal QoS routing trees and assign wavelengths to them. The objective is to minimize the number of wavelengths in the system. This is a challenging issue. It involves not only(More)
In this paper, we discuss the energy efficient multicast problem in ad hoc wireless networks. Each node in the network is assumed to have a fixed level of transmission power. The problem of our concern is: given an ad hoc wireless network and a multicast request, how to find a multicast tree such that the total energy cost of the multicast tree is(More)
Routing is one of the important steps in VLSI/ULSI physical design. The rectilinear Steiner minimum tree (RSMT) construction is an essential part of routing. Since macro cells, IP blocks, and pre-routed nets are often regarded as obstacles in the routing phase, obstacle-avoiding RSMT (OARSMT) algorithms are useful for practical routing applications. This(More)
Minimum m-connected k-dominating set problem is as follows: Given a graph G= (V ,E) and two natural numbers m and k, find a subset S ⊆ V of minimal size such that every vertex in V \ S is adjacent to at least k vertices in S and the induced graph of S is m-connected. In this paper we study this problem with unit disc graphs and small m, which is motivated(More)
Routing is one of the important phases in VLSI/ULSI physical design. The obstacle-avoiding rectilinear Steiner minimal tree (OARSMT) construction is an essential part of routing since macro cells, IP blocks, and pre-routed nets are often regarded as obstacles in the routing phase. Efficient OARSMT algorithms can be employed in practical routers iteratively.(More)
The star graph Sn is one of the most famous interconnection networks. It has been shown by Li [T.-K. Li, Cycle embedding in star graphs with edge faults, Appl. Math. Comput. 167 (2005) 891–900] that Sn contains a cycle of length from 6 to n! when the number of fault edges in the graph does not exceed n 3. In this paper, we improve this result by showing(More)
Obstacle-avoiding rectilinear Steiner minimal tree (OARSMT) construction is an essential part of routing. Recently, IC routing and related researches have been extended from Manhattan architecture (lambda<sub>2</sub>-geometry) to Y-/X-architecture (lambda<sub>3</sub>-lambda<sub>4</sub>-geometry) to improve the chip performance. This paper presents an O(n(More)