Massive Star Formation in the Molecular Ring Orbiting the Black Hole at the Galactic Center

A ring of dense molecular gas extending 2-7 pc orbits the supermassive black hole Sgr A* at the center of our Galaxy. Using the Green Bank Telescope, we detected water maser lines and both narrow (0.35 km/s) and broad (30 - 50 km/s) methanol emission from the molecular ring. Two of the strongest methanol lines at 44 GHz are confirmed as masers by interferometric observations. These class I methanol masers are collisionally excited and are signatures of early phases of massive star formation in the disk of the Galaxy, suggesting that star formation in the molecular ring is in its early phase. Close inspection of the kinematics of the associated molecular clumps in the HCN (J=1-0) line reveals broad red-shifted wings indicative of disturbance by protostellar outflows from young (few times 10^4 yr), massive stars embedded in the clumps. The thermal methanol profile has a similar shape, with a narrow maser line superimposed on a broad, red-shifted wing. Additional evidence for the presence of young massive protostars is provided by shocked molecular hydrogen and a number of striking ionized and molecular linear filaments in the vicinity of methanol sources suggestive of 0.5-pc scale protostellar jets. Given that the circumnuclear molecular ring is kinematically unsettled and thus is likely be the result of a recent capture, the presence of both methanol emission and broad, red-shifted HCN emission suggests that star formation in the circumnuclear ring is in its infancy.Comment: 13 pages, 4 figures, ApJ Letters (in press

L- and M-band imaging observations of the Galactic Center region

We present near-infrared H-, K-, L- and M-band photometry of the Galactic Center from images obtained at the ESO VLT in May and August 2002, using the NAOS/CONICA (H and K) and the ISAAC (L and M) instruments. The large field of view (70" x 70") of the ISAAC instrument and the large number of sources identified (L-M data for 541 sources) allows us to investigate colors, infrared excesses and extended dust emission. Our new L-band magnitude calibration reveals an offset to the traditionally used calibrations, which we attribute to the use of the variable star IRS7 as a flux calibrator. Together with new results on the extinction towards the Galactic Center (Scoville et al. 2003; Raab 2000), our magnitude calibration results in stellar color properties expected from standard stars and removes any necessity to modify the K-band extinction. The large number of sources for which we have obtained L-M colors allows us to measure the M-band extinction to A_M=(0.056+-0.006)A_V (approximately =A_L), a considerably higher value than what has so far been assumed. L-M color data has not been investigated previously, due to lack of useful M-band data. We find that this color is a useful diagnostic tool for the preliminary identification of stellar types, since hot and cool stars show a fairly clear L-M color separation. This is especially important if visual colors are not available, as in the Galactic Center. For one of the most prominent dust embedded sources, IRS3, we find extended L- and M-band continuum emission with a characteristic bow-shock shape. An explanation for this appearance is that IRS3 consists of a massive, hot, young mass-losing star surrounded by an optically thick, extended dust shell, which is pushed northwest by wind from the direction of the IRS16 cluster and SgrA*.Comment: 24 pages, 7 figures, 2 tables, accepted for publication in Astronomy & Astrophysic

First Light from the Far-Infrared Spectroscopy of the Troposphere (FIRST) Instrument

We present first light spectra from the new Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument. FIRST is a Fourier Transform Spectrometer developed to measure accurately the far-infrared (15 to 100 micrometers; 650 to 100 wavenumbers) emission spectrum of the Earth and its atmosphere. The observations presented here were obtained during a high altitude balloon flight from Ft. Sumner, New Mexico on 7 June 2005. The flight data demonstrate the instrument's ability to observe the entire energetically significant infrared emission spectrum (50 to 2000 wavenumbers) at high spectral and spatial resolution on a single focal plane in an instrument with one broad spectral bandpass beamsplitter. Comparisons with radiative transfer calculations demonstrate that FIRST accurately observes the very fine spectral structure in the far-infrared. Comparisons of the atmospheric window radiances measured by FIRST and by instruments on the NASA Aqua satellite that overflew FIRST are in excellent agreement. FIRST opens a new window on the spectrum that can be used for studying atmospheric radiation and climate, cirrus clouds, and water vapor in the upper troposphere

Surviving the hole I: Spatially resolved chemistry around Sgr A*

The interstellar region within the few central parsecs around the super-massive black hole, Sgr A* at the very Galactic center is composed by a number of overlapping molecular structures which are subject to one of the most hostile physical environments in the Galaxy. We present high resolution (4"x3"~0.16x0.11 pc) interferometric observations of CN, 13CN, H2CO, SiO, c-C3H2 and HC3N emission at 1.3 mm towards the central ~4 pc of the Galactic center region. Strong differences are observed in the distribution of the different molecules. The UV resistant species CN, the only species tracing all previously identified circumnuclear disk (CND) structures, is mostly concentrated in optically thick clumps in the rotating filaments around Sgr A*. H2CO emission traces a shell-like structure that we interpret as the expansion of Sgr A East against the 50 km/s and 20 km/s giant molecular clouds (GMCs). We derive isotopic ratios 12C/13C~15-45 across most of the CND region. The densest molecular material, traced by SiO and HC3N, is located in the southern CND. The observed c-C3H2/HC3N ratio observed in the region is more than an order of magnitude lower than in Galactic PDRs. Toward the central region only CN was detected in absorption. Apart from the known narrow line-of-sight absorptions, a 90 km/s wide optically thick spectral feature is observed. We find evidences of an even wider (>100 km/s) absorption feature. Around 70-75% of the gas mass, concentrated in just the 27% densest molecular clumps, is associated with rotating structures and show evidences of association with each of the arcs of ionized gas in the mini-spiral structure. Chemical differentiation has been proven to be a powerful tool to disentangle the many overlapping molecular components in this crowded and heavily obscured region.Comment: 12 pages, 22 figures. Accepted for publication in Astronomy and Astrophysic

Internet of things: where to be is to trust

[EN] Networks' creation is getting more and more required, anytime, anywhere. Devices that can participate on these networks can be quite different among them. Sensors, mobiles, home appliances, or other type of devices will have to collaborate to increase and improve the services provided to clients. In the same way, network configuration, security mechanisms establishment, and optimal performance control must be done by them. Some of these devices could have limited resources to work, sometimes even resources restriction not existing, they must work to optimize network traffic. In this article, we center our researching on spontaneous networks. We propose a secure spontaneous ad-hoc network, based on direct peer-to-peer interaction and communities' creation to grant a quick, easy, and secure access to users to surf the Web. Each device will have an identity in the network. Each community will also have an identity and will act as a unity on a world based on Internet connection. Security will be established in the moment they access to the network through the use of the trust chain generated by nodes. Trust is modified by each node on the basis of nodes behaviorLacuesta, R.; Palacios-Navarro, G.; Cetina Englada, C.; Peñalver Herrero, ML.; Lloret, J. (2012). Internet of things: where to be is to trust. EURASIP Journal on Wireless Communications and Networking. (203):1-16. doi:10.1186/1687-1499-2012-203S116203Lipnack J, Stamps J: Virtual Teams: Researching Across Space, Time, and Organizations with Technology. New York: John Wiley and Sons; 1997.Ahuja MK, Carley KN: Network structure in virtual organizations, organization science, Vol. 10, No. 6, Special Issue: Communication Processes for Virtual Organizations, November–December. 1999, 741-757.Mowshowitz A: Virtual organization. Commun ACM 1997, 40(9):30-37. 10.1145/260750.260759Preuß S: CH Cap, Overview of spontaneous networking-evolving concepts and technologies, in Rostocker Informatik-Berichte. Rostock: Fachbereich Informatik der Universit; 2000:113-123.Feeney LM, Ahlgren B, Westerlund A: Spontaneous networking: an application-oriented approach to ad hoc networking. IEEE Commun Mag 2001, 39(6):176-181. 10.1109/35.925687Latvakoski J, Pakkala D, Pääkkönen P: A communication architecture for spontaneous systems. IEEE Wirel Commun 2004, 11(3):36-42. 10.1109/MWC.2004.1308947Mani M, Nguyen A-M, Crespi N: SCOPE: a prototype for spontaneous P2P social networking. Proceedings of 8th IEEE International Conference on Pervasive Computing and Communications Workshops (PERCOM Workshops) 2010, 220-225.Legendre F, de Amorim MD, Fdida S: Implicit merging of overlapping spontaneous networks. Proceedings of Vehicular Technology Conference 2004, 3050-3054.Zarate Silva VH, De Cruz Salgado EI, Ramos Quintana F: AWISPA: an awareness framework for collaborative spontaneous networks. 36th Annual Frontiers in Education Conference 2006, 27-31.Perkins CE, Bhagwat P: Highly dynamic destination sequenced distance-vector routing (DSDV) for mobile computers. Proceedings of the Conference on Communications Architectures, Protocols and Applications (SIGCOMM’94 1994, 234-244.Johnson DB, Maltz DA, Broch J: DSR: The Dynamic Source Routing Protocol for Multihop Wireless Ad Hoc Networks. Boston, MA: Ad Hoc Networking (Addison-Wesley Longman Publishing; 2001.Perkins C, Belding-Royer E, Das S: Ad hoc on-demand distance vector (AODV) routing, RFC 3561. 2003.Park V, Corson MS: IETF MANET Internet Draft “draft-ietf-MANET-tora-spe03.txt”, November 2000. 2012. Accessed March http://tools.ietf.org/html/draft-ietf-manet-tora-spec-03Viana AC, De Amorim MD, Fdida S, de Rezende JF: Self-organization in spontaneous networks: the approach of DHT-based routing protocols. Ad Hoc Networks 2005, 3(5):589-606. 10.1016/j.adhoc.2004.08.006Lacuesta R, Peñalver L: IP addresses configuration in spontaneous networks. In Proceedings of the 9th WSEAS International Conference on Computers. Athens, Greece; 2005:1-6.Alvarez-Hamelin JI, Viana AC, de Amorim M Dias: Architectural considerations for a self-configuring routing scheme for spontaneous networks, Technical Report 1. 2005.Lacuesta R, Peñalver L: Automatic configuration of ad-hoc networks: establishing unique IP link-local addresses. In Proceedings of the International Conference on Emerging Security Information, Systems and Technologies (SECURWARE’07). Valencia, Spain; 2007:157-162.Foulks EF: Social network therapies and society: an overview. Contemp Fam Therapy 1985, 3(4):316-320.IBM: A Smarter Planet. 2012. http://www.ibm.com/smarterplanetMontenegro G, Kushalnagar N, Hui J, Culler D: RFC 4944: Transmission of IPv6 Packets over IEEE 802.15.4 Networks. 2007.Alcaraz C, Najera P, Lopez J, Roman R: Wireless Sensor Networks and the Internet of Things: Do We Need a Complete Integration?, 1st International workshop on the security of The internet of Things (SecIoT). tokyo (Japan); 2010. . Accessed January 2012 1er International Workshop on the Security of The Internet of Things (SecIoT 2010) http://www.nics.uma.es/seciot10/files/pdf/alcaraz_seciot10_paper.pdfFerscha A, Davies N, Schmidt A, Streitz N: Pervasive Socio-Technical Fabric. Procedia Computer Science 2011, 7: 88-91.Hubaux JP, Buttyán L, Capkun S: The quest for security in mobile ad-hoc networks, in Proceedings of the ACM Symposium on Mobile Ad-hoc Networking and Computing. 2001, 146-155.Wang Y, Varadharajan V: Interaction trust evaluation in decentralized environments, e-commerce and web technologies. In Proceedings of 5th International Conference on Electronic Commerce and Web Technologies, vol LNCS 3182. Springer; 2004:144-153.Jimin L, Junbao L, Aiguo A, Zhenpeng L: Two-way trust evaluation based on feedback. in Conference on Logistics Systems and Intelligent Management 2010, 3: 1910-1914.Daskapan S, Nurtanti I, Van den Berg J: Trust algorithms in P2P file sharing networks. Int J Internet Technol Secured Trans 2010, 2(1–2):174-200.Maña A, Koshutanski H, Pérez EJ: A trust negotiation based security framework for service provisioning in load-balancing clusters. Comput Secur 2012, 31(1):4-25. 10.1016/j.cose.2011.11.006Stajano F, Anderson R: The resurrecting duckling security issues for ad-hoc wireless networks. Security Protocols, 7th International Workshop Proceedings, Lecture notes in Computer Science, LNCS 1296 1999, 172-194.Balfanz D, Smetters DK, Stewart P, ChiWong H: Talking to strangers: authentication in ad-hoc wireless networks, in Symposium on Network and Distributed Systems Security (NDSS’02). San Diego, CA; 2002.Capkun S, Hubaux JP, Buttyán L: Mobility helps security in ad-hoc networks. In Proceedings of the 4th ACM international symposium on Mobile ad hoc networking & computing. MD, USA: Annapolis; 2003:46-56.Metzger MJ: Privacy, trust, and disclosure: exploring barriers to electronic commerce. J Comput-Mediat Commun 2004, 9(4). http://jcmc.indiana.edu/vol9/issue4/metzger.html 2004, 9(4)

A spontaneous ad hoc network to share www access

In this paper, we propose a secure spontaneous ad-hoc network, based on direct peer-to-peer interaction, to grant a quick, easy, and secure access to the users to surf the Web. The paper shows the description of our proposal, the procedure of the nodes involved in the system, the security algorithms implemented, and the designed messages. We have taken into account the security and its performance. Although some people have defined and described the main features of spontaneous ad-hoc networks, nobody has published any design and simulation until today. Spontaneous networking will enable a more natural form of wireless computing when people physically meet in the real world. We also validate the success of our proposal through several simulations and comparisons with a regular architecture, taking into account the optimization of the resources of the devices. Finally, we compare our proposal with other caching techniques published in the related literature. The proposal has been developed with the main objective of improving the communication and integration between different study centers of low-resource communities. That is, it lets communicate spontaneous networks, which are working collaboratively and which have been created on different physical places.Authors want to give thanks to the anonymous reviewers for their valuable suggestions, useful comments, and proofreading of this paper. This work was partially supported by the Ministerio de Educacion y Ciencia, Spain, under Grant no. TIN2008-06441-C02-01, and by the "Ayudas complementarias para proyectos de I+D para grupos de calidad de la Generalitat Valenciana" (ACOMP/2010/005).Lacuesta Gilaberte, R.; Lloret, J.; García Pineda, M.; Peñalver Herrero, ML. (2010). A spontaneous ad hoc network to share www access. EURASIP Journal on Wireless Communications and Networking. 2010:1-16. https://doi.org/10.1155/2010/232083S1162010Preuß S, Cap CH: Overview of spontaneous networking-evolving concepts and technologies. In Rostocker Informatik-Berichte. Volume 24. Fachbereich Informatik der Universit at Rostock; 2000:113-123.Gallo S, Galluccio L, Morabito G, Palazzo S: Rapid and energy efficient neighbor discovery for spontaneous networks. Proceedings of the 7th ACM International Symposium on Modeling, Analysis and Simulation of Wireless and Mobile Systems, October 2004, Venice, ItalyLatvakoski J, Pakkala D, Pääkkönen P: A communication architecture for spontaneous systems. IEEE Wireless Communications 2004, 11(3):36-42. 10.1109/MWC.2004.1308947Zarate Silva VH, De Cruz Salgado EI, Quintana FR: AWISPA: an awareness framework for collaborative spontaneous networks. Proceedings of the 36th ASEE/IEEE Frontiers in Education Conference (FIE '06), October 2006 1-6.Feeney LM, Ahlgren B, Westerlund A: Spontaneous networking: an application-oriented approach to ad hoc networking. IEEE Communications Magazine 2001, 39(6):176-181. 10.1109/35.925687Perkins CE, Bhagwat P: Highly dynamic destination-sequenced distance-vector routing (DSDV) for mobile computers. Proceedings of the Conference on Communications Architectures, Protocols and Applications (SIGCOMM '94), August 1994 234-244.Johnson DB, Maltz DA, Broch J: DSR: The Dynamic Source Routing Protocol for Multihop Wireless Ad Hoc Networks, Ad Hoc Networking. Addison-Wesley Longman Publishing, Boston, Mass, USA; 2001.Perkins C, Belding-Royer E, Das S: Ad hoc on-demand distance vector (AODV) routing. RFC 3561, July 2003Park V, Corson MS: IETF MANET Internet Draft "draft-ietf-MANET-tora-spe03.txt". Novemmer 2000.Viana AC, De Amorim MD, Fdida S, de Rezende JF: Self-organization in spontaneous networks: the approach of DHT-based routing protocols. Ad Hoc Networks 2005, 3(5):589-606.Gilaberte RL, Herrero LP: IP addresses configuration in spontaneous networks. Proceedings of the 9th WSEAS International Conference on Computers, July 2005, Athens, GreeceViana AC, Dias de Amorim M, Fdida S, de Rezende JF: Self-organization in spontaneous networks: the approach of DHT-based routing protocols. Ad Hoc Networks 2005, 3(5):589-606.Alvarez-Hamelin JI, Carneiro Viana A, Dias De Amorim M: Architectural considerations for a self-configuring routing scheme for spontaneous networks.,Tech. Rep. 1 October 2005.Lacuesta R, Peñalver L: Automatic configuration of ad-hoc networks: establishing unique IP link-local addresses. Proceedings of the International Conference on Emerging Security Information, Systems and Technologies (SECURWARE '07), October 2007, Valencia, SpainFoulks EF: Social network therapies and society: an overview. Contemporary Family Therapy 1985, 3(4):316-320.Wang Y, Wu H: DFT-MSN: the delay/fault-tolerant mobile sensor network for pervasive information gathering. Proceedings of the 25th IEEE International Conference on Computer Communications (INFOCOM '06), April 2006Kindberg T, Zhang K: Validating and securing spontaneous associations between wireless devices. In Proceedings of the 6th Information Security Conference (ISC '03), 2003. Springer; 44-53.Al-Jaroodi J: Routing security in open/dynamic mobile ad hoc networks. The International Arab Journal of Information Technology 2007, 4(1):17-25.Stajano F, Anderson RJ: The resurrecting duckling: security issues for ad-hoc wireless networks. Proceedings of the 7th International Workshop on Security Protocols, April 1999 172-194.Zhou L, Haas ZJ: Securing ad hoc networks. IEEE Network 1999, 13(6):24-30. 10.1109/65.806983Hauspie M, Simplot-Ryl I: Cooperation in ad hoc networks: enhancing the virtual currency based models. Proceedings of the 1st International Conference on Integrated Internet Ad Hoc and Sensor Networks (InterSense '06), May 2006, Nice, FranceWang X, Dai F, Qian L, Dong H: A way to solve the threat of selfish and malicious nodes for ad hoc networks. Proceedings of the International Symposium on Information Science and Engieering (ISISE '08), December 2008, Shanghai, China 1: 368-370.Kargl F, Klenk A, Weber M, Schlott S: Sensors for detection of misbehaving nodes in MANETs. Detection of Intrusion and Malware and Vulnerability Assessment (DIMVA '04), July 2004, Dortmund, Germany 83-97.Kargl F, Geiss A, Scholott S, Weber M: Secure dynamic source routing. Proceedings of the 38th Annual Hawaii International Conference on System Sciences (HICSS '05), January 2005, Big Island, Hawaii, USAGokhale S, Dasgupta P: Distributed authentication for peer-to-peer networks. Proceedings of the Symposium on Applications and the Internet Workshops, January 2003 347-353.Capkun S, Buttyán L, Hubaux J-P: Self-organized public-key management for mobile ad hoc networks. IEEE Transactions on Mobile Computing 2003, 2(1):52-64. 10.1109/TMC.2003.1195151Stajano F, Anderson R: The resurrecting duckling security issues for ad-hoc wireless networks. In Proceedings of the 7th International Workshop on Security Protocols, 1999, Berlin, Germany, Lecture Notes in Computer Science. Volume 1796. Springer; 172-194.Balfanz D, Smetters DK, Stewart P, Wong HC: Talking to strangers: authentication in ad-hoc wireless networks. Proceedings of the International Symposium on Network and Distributed Systems Security (NDSS '02), February 2002, San Diego, Calif, USABarbara D, Imielinski T: Sleepers and workaholics: caching strategies in mobile environments. Proceedings of the ACM SIGMOD International Conference on Management of Data, May 1994 1-12.Cao G: A scalable low-latency cache invalidation strategy for mobile environments. IEEE Transactions on Knowledge and Data Engineering 2003, 15(5):1251-1265. 10.1109/TKDE.2003.1232276Hu Q, Lee D: Cache algorithms based on adaptive invalidation reports for mobile environments. Cluster Computing 1998, 1(1):39-50. 10.1023/A:1019012927328Jing J, Elmagarmid A, Helal A, Alonso R: Bit-sequences: an adaptive cache invalidation method in mobile client/server environments. Mobile Networks and Applications 1997, 2(2):115-127. 10.1023/A:1013616213333Kahol A, Khurana S, Gupta S, Srimani P: An efficient cache management scheme for mobile environment. Proceedings of the 20th International Conference on Distributied Computing System (ICDCS '00), April 2000, Taipei, Taiwan 530-537.Kazar M: Synchronization and caching issues in the Andrew file system. Proceedings of USENIX Conference, February 1988, Dallas, Tex, USA 27-36.Roussopoulos M, Baker M: CUP: controlled update propagation in peer-to-peer networks. Proceedings of USENIX Annual Technical Conference, June 2003, San Antonio, Tex, USASandberg S, Kleiman S, Goldberg D, Walsh D, Lyon B: Design and implementation of the sun network file system. Proceedings of USENIX Summer Conference, June 1985, Portland, Ore, USA 119-130.Wu K, Yu PS, Chen M: Energy-efficient caching for wireless mobile computing. Proceedings of the 12th IEEE International Conference on Data Engineering, February-March 1996, New Orleans, La, USA 336-343.Yeung MKH, Kwok Y-K: Wireless cache invalidation schemes with link adaptation and downlink traffic. IEEE Transactions on Mobile Computing 2005, 4(1):68-83.Wessels D, Claffy K: Internet cache protocol (IC) v.2. http://www.ietf.org/rfc/rfc2186.txtFan L, Cao P, Almeida J, Broder AZ: Summary cache: a scalable wide-area web cache sharing protocol. IEEE/ACM Transactions on Networking 2000, 8(3):281-293. 10.1109/90.851975Dykes SG, Robbins KA: A viability analysis of cooperative proxy caching. Proceedings of the 20th Annual Joint Conference of the IEEE Computer and Communications Societies (INFOCOM '01), April 2001, Anchorage, Alaska, USA 3: 1205-1214.Wessels D, Claffy K: RFC 2186: Internet cache protocol (ICP), version 2. The Internet Engineering Taskforce, September 1997Wessels D, Claffy K: RFC 2187: application of internet cache protocol (ICP), version 2. The Internet Engineering Taskforce, September 1997Ren Q, Dunhan MH: Using semantic caching to manage location dependent data in mobile computing. Proceedings of the 6th Annual International Conference on Mobile Computing and Networking, August 2000, Boston, Mass, USA 210-221.Lim S, Lee W-C, Cao G, Das CR: Cache invalidation strategies for internet-based mobile ad hoc networks. Computer Communications 2007, 30(8):1854-1869. 10.1016/j.comcom.2007.02.020Park B-N, Lee W, Lee C: QoS-aware internet access schemes for wireless mobile ad hoc networks. Computer Communications 2007, 30(2):369-384. 10.1016/j.comcom.2006.09.004Hara T: Effective replica allocation in ad hoc networks for improving data accessibility. Proceedings of the 20th Annual Joint Conference of the IEEE Computer and Communications Societies (INFOCOM '01), April 2001, Anchorage, Alaska, USA 1568-1576.Papadopouli M, Schulzrinne H: Effects of power conservation, wireless converage and cooperation on data dissemination among mobile devices. Proceedings of the ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc '01), October 2001, Long Beach, Calif, USA 117-127.Can P, Irani S: Cost-aware WWW proxy caching algorithms. Proceedings of the USENIX Symposium on lnternet Technology and Systems, December 1997Rizzo L, Vicisano L: Replacement policies for a proxy cache. IEEE/ACM Transactions on Networking 2000, 8(2):158-170. 10.1109/90.842139Williams S, Abrams M, Strandridge CR, Abdulla G, Fox EA: Removal policies in network caches for world-wide web documents. Proceedings of the ACM SIGCOMM Conference on Applications, Technologies, Architectures, and Protocols for Computer Communications, August 1996, Palo Alto, Calif, USA 293-305.Hara T: Replica allocation in ad hoc networks with period data update. 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Proceedings of the 18th IEEE Symposium on Reliable Distributed Systems (SRDS '99), October 1999, Lausanne, Switzerland 4-13.Corson MS, Macker JP, Cirincione GH: Internet-based mobile ad hoc networking. IEEE Internet Computing 1999, 3(4):63-70. 10.1109/4236.780962Lim S, Lee W-C, Cao G, Das CR: A novel caching scheme for improving internet-based mobile ad hoc networks performance. Ad Hoc Networks 2006, 4(2):225-239. 10.1016/j.adhoc.2004.04.013Opnet Modeler http://www.opnet.com/solutions/network_rd/modeler_wireless.htmlLacuesta R, Lloret J, Garcia M, Peñalver L: Two secure and energy-saving spontaneous ad-hoc protocol for wireless mesh client networks. Journal of Network and Computer Applications. In pres

Tutkasensori ja häiveet osana sensorijärjestelmiä

Tämän tekniikan kandidaatintyön tavoitteena on opiskella sensorijärjestelmien, tutkasensorin sekä häiveteknologian perustoimintaperiaatteet. Lisäksi tavoitteena on muodostaa käsitys näiden teknologioiden kehitysnäkökulmista ja haasteista tulevaisuudessa. Työ toteutetaan käyttämällä kirjalähteitä sekä muita saatavia verkkolähteitä. Työn tuloksena voidaan todeta, että sensorijärjestelmien, tutkasensonsereiden ja häivetekniikan perustoimintaperiaatteeet ovat olleet tunnettuja jo pitkään, mutta erityisesti autonomisten ja älykkäiden järjestelmien kehitys lisää aiheena olevien teknologioiden kehitystä tulevaisuudessa. Toisaalta kehitys tuo myös haasteita kuten eettiset, lainsäädännölliset sekä kyberturvallisuuden ongelmat.Goal of this bachelor’s thesis is to study the principle of sensor systems, radar sensor and stealth technology. On top of that the goal is to constitute an understanding of development and challenges of these technologies in the future. The work will be carried out using book sources and other online sources. It is stated as a result that the principle of sensor systems, radar sensor and stealth technology have been known for a long time but especially the development of autonomous and intelligent systems increase the development of these technologies in the future. On the other hand side the development brings challenges as ethical, legislation and cyber security problems

Future urban smartness: Connectivity zones with disposable identities

We tie the Smart Cities concept to the On-Life human-centered vision. The need to provide citizen-focused empowering visions of smart cities planning and development is very much needed, especially when a post-COVID environment requires urban growth “resets” within stringent sustainability limits. Our selected case studies describe some of these current challenges. Two novel utopian visions of technology are proposed: urban “cold spots” and “disposable identities.” The aim is to safeguard human digital rights in the digital smart urban sphere: our cherished freedom of expression, privacy, autonomy, and civic assembly. The chapter has three parts, the limits of smartness; the IoT, 5G, and 6G technology developments of cyber physical systems; and the need to choose a suitable form of identity management. Authors bring together their intradisciplinary approach

Smartphones as Integrated Kinematic and Dynamic Sensors for Amusement Park Physics Applications

Abstract. Spontaneous Multi-hop Networks (SMNs) are emerging as a novel networking and communication paradigm, strongly pushed by the widespread availability of smartphones equipped with heterogeneous wireless connectivity and powerful computing capabilities. SMN nodes can opportunistically exploit peer-to-peer contacts to seamlessly share resources/content in an impromptu and transient way. The paper presents a novel 3-layer modeling abstraction for multicast in SMNs, in order to characterize the different kinds of possible internode interaction based on different degrees of expressiveness and social-aware collaboration. In addition, we originally present the design and implementation of some novel semantic-based multicast mechanisms that efficiently target SMN nodes based on user interests and that are integrated into our SMN middleware solution. First preliminary results show the feasibility of the approach and its limited overhead