Curvature corrections and Kac-Moody compatibility conditions

We study possible restrictions on the structure of curvature corrections to gravitational theories in the context of their corresponding Kac--Moody algebras, following the initial work on E10 in Class. Quant. Grav. 22 (2005) 2849. We first emphasize that the leading quantum corrections of M-theory can be naturally interpreted in terms of (non-gravity) fundamental weights of E10. We then heuristically explore the extent to which this remark can be generalized to all over-extended algebras by determining which curvature corrections are compatible with their weight structure, and by comparing these curvature terms with known results on the quantum corrections for the corresponding gravitational theories.Comment: 27 page

Adaptive Error Control Using Arq And Bch Codes In Sensor Networks Using Coverage Area Information

This paper proposes adaptive error control strategies for wireless sensor networks using informational value of messages. The informational value is based on sensors coverage area. Important packets are protected by more powerful error control schemes than less important packets. BCH codes and retransmission schemes were analyzed using OQPSK modulation in Rayleigh fading channels. The results obtained show that the adaptive schemes improve the reliability of packets with high informational value without a significant increase in the energy consumption. ©2009 IEEE.RIEC Tohoku University,IEEE,IEEE Communications Society,National Institute of Information and,Communications Technology (NiCT)Akyildiz, I.F., Su, W., Sankarasubramaniam, Y., Cayirci, E., A survey on sensor networks (2002) IEEE Communications Magazine, pp. 102-114. , AugustDesset, C., Fort, A., Selection of channel coding for low-power wireless systems Proc. IEEE Vehicular Technology Conference, Jeju, Korea, April 2003Howard, S.L., Schlegel, C., Iniewski, K., Error control coding in low-power wireless sensor networks when is ECC energy-efficient? (2006) EURASIP Journal on Wireless Communications and Networking, 2, pp. 1-14. , MarchKarvonen, H., Shelby, Z., Pomala-Ráez, C., Coding for energy efficient wireless embedded networks International Workshop on Wireless Ad-hoc Networks, 2004Kashani, Z.H., Shiva, M., BCH coding and multihop communication in wireless sensor networks Third IEEE IFIP Int. Conference on Wireless and Optical Communications Networks, Bangalore, India, April 2006Kleinschmidt, J.H., Borelli, W.C., Pellenz, M.E., An energy efficiency model for adaptive and custom error control schemes in Bluetooth sensor networks (2009) AEU - International Journal of Electronics and CommunicationsKöpke, A., Karl, H., Löbbers, M., Using energy where it counts: Protecting important messages in the link layer Proc. of the 2 nd European Workshop on Wireless Sensor Networks, Istanbul, Turkey, January 2005Liu, H., Ma, H., El Zarki, M., Gupta, S., Error control schemes for networks: An overview (1997) Mobile Networks and Applications, 2 (2), pp. 167-182Raghunathan, V., Schurgers, C., Park, S., Srivastava, M.B., Energy aware wireless micro sensor networks (2002) IEEE Signal Processing, pp. 40-50. , MarchSankarasubramanian, Y., Akyildiz, I.F., Mc Laughlin, S.W., Energy efficiency based packet size optimization in wireless sensor networks Proc. of Sensor Network Protocols and Applications, Anchorage, USA, May 2003Shelby, Z., Pomalaza-Raez, C., Karvonen, H., Haapola, J., Energy optimization in multihop wireless embedded and sensor networks (2005) International Journal of Wireless Information Networks, 12 (1), pp. 11-21. , DOI 10.1007/s10776-005-5166-1Sklar, B., (1995) Digital Communications, , Prentice-HallVuran, M.C., Akyildiz, I.F., Cross-layer analysis of error control in wireless sensor networks (2006) IEEE SECONZorzi, M., Rao, R.R., Coding tradeoffs for reduced energy consumption in sensor networks IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, Barcelona, Spain, September 200

Power Efficient Error Control For Bluetooth-based Sensor Networks

This paper- studies different error control schemes in wireless sensor networks with Bluetooth technology. The tradeoff between reliability and energy consumption of Bluetooth packets are analyzed, using different error control techniques, such as retransmission and channel coding The AUX1 packet is utilized for custom coding and also are proposed adaptive techniques based on the number of hops of the network. The wireless channel is modeled with Rayleigh fading. The results obtained may be used as references to determine the packet type in a sensor application. © 2005 IEEE.2005284291Akyildiz, I.F., Su, W., Sankarasubramaniam, Y., Cayirci, E., A survey on sensor networks (2002) IEEE Communications Magazine, pp. 102-114. , AugustSpecifications of the bluetooth system (2003) Core Version 1.2, , http://www.bluetooth.com, NovemberKasten, O., Langheinrich, M., First experiences with Bluetooth in the smart-its distributed sensor network (2001) Workshop on Ubiquitous Computing and Communications, , Barcelona, Spain, SeptemberLeopold, M., Dydensborg, M.D., Bonnet, P., Bluetooth and sensor networks: A reality check (2003) 1 st ACM Conference on Sensor Systems, , Los Angeles, CA, USA, NovemberMehta, V., El Zarki, M., Bluetooth based sensor network for civil infrastructure health monitoring (2004) Wireless Networks, 10, pp. 401-412. , Kluwer Academic Publishers, JulySaginbekov, S., Korpeoglu, I., An energy efficient scatternet formation algorithm for Bluetooth-based sensor networks (2005) 2 nd European Workshop on Wireless Sensor Networks, , Istanbul, Turkey, FebruaryMathias, H., Jan, D., Dirk, T., Energy-efficient data collection for Bluetooth-based sensor networks (2004) IEEE Instrumentation and Measurement Technology Conference, , Italy, MayValenti, M.C., Robert, M., Reed, J.H., On the throughput of Bluetooth data transmissions (2002) IEEE Wireless Communications and Networking Conference, , Orlando, USA, MarchValenti, M.C., Robert, M., Custom coding, adaptive rate control and distributed detection for Bluetooth (2002) Proc. IEEE Vehicular Technology Conference, , Vancouver, BC, SeptemberMeer, J., Nijdam, M., Bijl, M., Adaptive error control in a wireless sensor network using packet importance valuation (2003) Hardware/software Co-design, , Enschede, Netherlands, MayProakis, J., (2001) Digital Communications, , New York, NY: McGraw-Hill, 4 th editionKleinschmidt, J.H., Pellenz, M.E., Lima Jr., L.A.P., Evaluating and improving Bluetooth piconet performance over Nakagami-m fading channels (2004) Proc. of the Ninth IEEE International Symposium on Computers and Communications, , Alexandria, Egypt, JulyDesset, C., Fort, A., Selection of channel coding for low-power wireless systems (2003) Proc. IEEE Vehicular Technology Conference, , Jeju, Korea, Apri

An Analytical Model For Energy Efficiency Of Error Control Schemes In Sensor Networks

This paper analyzes the energy efficiency of wireless sensor networks using different error control schemes. An analytical model is presented to evaluate the energy efficiency in Nakagami-m fading channels. The model is applied to error control schemes of Bluetooth technology. Some custom error control schemes and adaptive techniques using different FEC and ARQ strategies are analyzed. Performance results are obtained through analysis for networks with different number of hops and fading channel conditions. © 2007 IEEE.38953900Akyildiz, I.F., Su, W., Sankarasubramaniam, Y., Cayirci, E., A survey on sensor networks (2002) IEEE Communications Magazine, pp. 102-114. , AugustSankarasubramaman, Y., Akyildiz, I.F., Mc Laughlin, S.W., Energy efficiency based packet size optimization in wireless sensor networks (2003) Proc. of Sensor Network Protocols and ApplicationsKarvonen, H., Shelby, Z., Pomala-Ráez, C., Coding for energy efficient wireless embedded networks (2004) Int. Workshop on Wireless Ad-hoc NetworksMeer, J., Nijdam, M., Bijl, M., Adaptive error control in a wireless sensor network using packet importance valuation (2003) Hardware/software co-design, , Enschede, Netherlands, MayKleinschmidt, J.H., Borelli, W.C., Pellenz, M.E., Power efficient error control for Bluetooth-based sensor networks (2005) IEEE Local Computer Networks Conference, , Sydney, Australia, NovemberKleinschmidt, J.H., Borelli, W.C., Pellenz, M.E., Custom error control schemes for energy efficient Bluetooth sensor networks (2006) SBrT/IEEE International Telecommunications Symposium, , Fortaleza, Brazil, SeptemberLiu, H., Ma, H., El Zarki, M., Gupta, S., Error control schemes for networks: An overview (1997) Mobile Networks and Applications, 2, pp. 167-182. , JuneValenti, M.C., Robert, M., Reed, J.H., On the throughput of Bluetooth data transmissions (2002) IEEE Wireless Communications and Networking Conference, , Orlando, USA, MarchSpecifications of the Bluetooth system, , http://www.bluetooth.com, Core Version 1.2, November 2003Mehta, V., El Zarki, M., Bluetooth based sensor network for civil infrastructure health monitoring (2004) Wireless Networks, 10, p. 401412. , Kluwer Academic Publishers, JulyNegri, L., Zanetti, D., Power/performance tradeoffs in Bluetooth sensor networks (2006) Proc. of the 39th Annual Hawaii Int. Conference on System Sciences, , Hawaii, USA, JanuaryZhang, X., Riley, G.R., Energy-aware on-demand scatternet formation and routing for Bluetooth-based wireless sensor networks (2005) IEEE Communications Magazine, 43 (7), pp. 126-133. , JulyValenti, M.C., Robert, M., Custom coding, adaptive rate control and distributed detection for Bluetooth (2002) Proc. IEEE Vehicular Technology Conference, , Vancouver, BC, SeptemberRaghunathan, V., Schurgers, C., Park, S., Srivastava, M.B., Energy aware wireless micro sensor networks (2002) IEEE Signal Processing, pp. 40-50. , Marc

Association of neighboring β-strands of outer membrane protein A in lipid bilayers revealed by site-directed fluorescence quenching

We present a detailed study on the formation of neighboring β-strands during the folding of a monomeric integral membrane protein of the β-barrel type. β-Strand and β-barrel formations were investigated for the eight-stranded transmembrane domain of outer membrane protein A (OmpA) with single-tryptophan (W), single-cysteine (C) OmpA mutants. Based on the OmpA structure, W and C were introduced in two neighboring β-strands oriented toward the hydrocarbon core of the membrane. Replaced residue pairs were closer to either the periplasmic turns (named cis-side) or the outer loops (named trans-side) of the strand. WnCm OmpA mutants containing W at position n and C at position m along the polypeptide chain were labeled at the C by a nitroxyl spin label, which is a short-range fluorescence quencher. To monitor the association of neighboring β-strands, we determined the proximity between fluorescent W and labeled C in OmpA folding experiments by intramolecular fluorescence quenching. Formation of native β-strand contacts in folding experiments required the lipid membrane. Residues in the trans-side of strands β1, β2, and β3, represented by mutants W15C35 (β1β2, trans) and W57C35 (β3β2, trans), reached close proximity prior to residues in the N(β1)- and C(β8)-terminal strands as examined for mutants W15C162 (β1β8, trans) and W7C170 (β1β8, cis). Tryptophan and cysteine converged slightly faster in W15C162 (β1β8, trans) than in W7C170 (β1β8, cis). The last folding step was observed for residues at the cis-ends of strands β1 and β2 for the mutant W7C43 (β1β2, cis). The data also demonstrate that the neighboring β-strands associate upon insertion into the hydrophobic core of the lipid bilayer

Dna Sequences Generated By ℤ4-linear Codes

One of the puzzling problems in mathematical biology is to show the existence of any form of error-correcting code in the DNA structure. Here we propose a model for the biological coding system similar to that of a digital communication system. This model consists of an encoder (a mapper and a BCH code over ℤ4) and a modulator (genetic code). Here we show that DNA sequences including proteins and targeting sequences from different species with 63, 255, and 1023 nucleotides long were identified as codewords of ℤ4-linear codes. © 2010 IEEE.13201324Schneider, T.D., Information content of individual genetic sequences (1997) Journal of Theoretical Biology, 189, pp. 427-441Liebovitch, L.S., Tao, Y., Todorov, A.T., Levine, L., Is there an error correcting code in the base sequence in DNA? (1996) Biophysical Journal, 71, pp. 1539-1544Rosen, G.L., Examining coding structure and redundancy in DNA (2006) IEEE Engineering in Medicine and Biology, 25, pp. 62-68May, E., Vouk, M., Bitzer, D., Rosnick, D., An error-correcting code framework for genetic sequence analysis (2004) Journal of the Franklin Institute, 34, pp. 89-109Battail, G., Information theory and error correcting codes in genetics and biological evolution (2006) Introduction to Biosemiotics, , Springer: New York, USAYockey, H., (1992) Information Theory and Molecular Biology, , Cambridge University Press: CambridgeDawy, Z., Hanus, P., Weindl, J., Dingel, J., Morcos, F., On genomic coding theory (2007) European Transactions on Telecommunications, 18, pp. 873-879Loeliger, H.A., Signal sets matched to groups (1991) IEEE Trans. Inform. Theory, IT-37, pp. 1675-1682Forney, G.D., Geometrically uniform codes (1991) IEEE Trans. Inform. Theory, IT-37, pp. 1241-1260Hammons, A.R., Kumar, P.V., Calderbank, A.R., Sloane, N.J.A., Sole, P., The Z4-linearity of kerdock, preparata, goethals, and related codes (1994) IEEE Trans. Inform. Theory, IT-40, pp. 301-319Gerônimo, J.R., Palazzo Jr., R., Interlando, J.C., Alves, M.M.S., Costa, S.I.R., The symmetry group of ℤq N in the Lee space and the ℤq N-linear codes (1997) Lecture Notes in Computer Science, 1255, pp. 66-77Alves, M.M.S., Araújo, M.C., Palazzo Jr., R., Costa, S.I.R., Interlando, J.C., Relating propelinear and G-linear codes (2001) Discrete Mathematics, 243 (1-3), pp. 187-194Nordstrom, A.W., Robinson, J.P., An optimum nonlinear code (1967) Info. and Control, 11, pp. 613-616Preparata, F.P., A class of optimum nonlinear double-error correcting codes (1968) Info. and Control, 13, pp. 378-400McWillians, F.J., Sloane, N.J.A., (1977) The Theory of Error Correcting Codes, , North-Holland Publishing CompanyPeterson, W.W., Weldon Jr., E.J., (1972) Error-Correcting Codes, , 2nd edition, MIT PressInterlando, J.C., Palazzo Jr., R., Elia, M., On the decoding of BCH and Reed-Solomon codes over integer residues rings (1997) IEEE Trans. Inform. Theory, IT-43 (3), pp. 1013-1021Andrade, A.A., Palazzo Jr., R., Construction and decoding of BCH codes over finite commutative rings (1999) Linear Algebra and its Applications, 286, pp. 69-85Elia, M., Interlando, J.C., Palazzo Jr., R., Computing the reciprocal of units in finite Galois rings (2000) Journal of Discrete Mathematical Sciences and Cryptography, 3 (1-3), pp. 41-55Andrade, A.A., Palazzo Jr., R., Alternant and BCH codes over certain local finite rings (2003) Computational and Applied Mathematics, 22 (2), pp. 233-247Shankar, P., On BCH codes over arbitrary integer rings (1979) IEEE Transactions on Information Theory, IT-25 (4), pp. 480-48