{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,28]],"date-time":"2025-10-28T00:27:27Z","timestamp":1761611247079,"version":"build-2065373602"},"reference-count":24,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2009,6,30]],"date-time":"2009-06-30T00:00:00Z","timestamp":1246320000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The paper considers the connected target coverage (CTC) problem in wireless heterogeneous sensor networks (WHSNs) with multiple sensing units, termed MU-CTC problem. MU-CTC problem can be reduced to a connected set cover problem and further formulated as an integer linear programming (ILP) problem. However, the ILP problem is an NP-complete problem. Therefore, two distributed heuristic schemes, REFS (remaining energy first scheme) and EEFS (energy efficiency first scheme), are proposed. In REFS, each sensor considers its remaining energy and its neighbors\u2019 decisions to enable its sensing units and communication unit such that all targets can be covered for the required attributes and the sensed data can be delivered to the sink. The advantages of REFS are its simplicity and reduced communication overhead. However, to utilize sensors\u2019 energy efficiently, EEFS is proposed. A sensor in EEFS considers its contribution to the coverage and the connectivity to make a better decision. To our best knowledge, this paper is the first to consider target coverage and connectivity jointly for WHSNs with multiple sensing units. Simulation results show that REFS and EEFS can both prolong the network lifetime effectively. EEFS outperforms REFS in network lifetime, but REFS is simpler.<\/jats:p>","DOI":"10.3390\/s90705173","type":"journal-article","created":{"date-parts":[[2009,6,30]],"date-time":"2009-06-30T12:29:39Z","timestamp":1246364979000},"page":"5173-5200","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":23,"title":["On Connected Target Coverage for Wireless Heterogeneous Sensor Networks with Multiple Sensing Units"],"prefix":"10.3390","volume":"9","author":[{"given":"Kuei-Ping","family":"Shih","sequence":"first","affiliation":[{"name":"Department of Computer Science & Information Engineering, Tamkang University, Tamshui 251, Taipei, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Der-Jiunn","family":"Deng","sequence":"additional","affiliation":[{"name":"Department of Computer Science & Information Engineering, National Changhua University of Education, Changhua, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ruay-Shiung","family":"Chang","sequence":"additional","affiliation":[{"name":"Department of Computer Science & Information Engineering, National Dong Hwa University, Hualien, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hung-Chang","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Information Technology, Ching Kuo Institute of Management and Health, Keelung, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2009,6,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"393","DOI":"10.1016\/S1389-1286(01)00302-4","article-title":"Wireless Sensor Networks: A Survey","volume":"38","author":"Akyildiz","year":"2002","journal-title":"Comput. 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