Nils
Christophersen
Department
of Informatics
List
of publications
Papers
in peer reviewed journals
Dahl, T., S.S. Pereira, N. Christophersen, and D. Gesbert, 2007. Intrinsic subspace convergence in TDD MIMO communication, IEEE
Trans. Signal Processing, 55(6), 2676-2687.
Dahl,
T., N. Christophersen and D. Gesbert, 2004. Blind
MIMO eigenmode transmission
based on the algebraic power method, IEEE Trans. Signal Processing, 52(9),
2424-2431.
Bølviken, E., P. Acklam, N. Christophersen, and J.M. Størdal, 2001. Monte-Carlo
filters for non-linear state estimation, Automatica,
37(2), 177-183.
Lingjærde, O.C. and N. Christophersen, 2000.
Shrinkage Structure of Partial Least Squares, Scandinavian Journal of
Statistics, 27(3), 459-473.
Aamlid, D., K. Tørseth, K. Venn, A.O. Stuanes, S. Solberg, G. Hylen, N.
Christophersen, and E. Framstad, 2000. Changes of forest health in Norwegian
boreal forests during 15 years, Forest Ecology and Management, 127(1-3),
103-118.
Tømte, O.T., K.L. Seip, and N. Christophersen, 1998. Evidence that loss in
predictability increases with weakening of (metabolic) links to physical
forcing functions in aquatic ecosystems, Oikos, 82,
325-332.
Kugiumtzis, D., O.C. Lingjærde,
and N. Christophersen, 1998. Regularized local linear prediction of chaotic
time series, Physica D, 112, 344-360.
Akerjord, M.A., N. Christophersen, 1996. Assessing mixing models within a
common framework, Env. Sci.
Tech., 30, 2105-2112.
Hauhs, M., C. Neal, R.P. Hooper, and N.
Christophersen, 1996. Summary of a workshop on ecosystem modelling: The end of
an area?, Sci. Tot. Env.,
183, 1-5.
Mulder, J., N. Christophersen, K. Kopperud, and P.H. Fjeldal, 1995, Water
flow paths and the spatial distribution of soils as a key to understanding
differences in streamwater chemistry between three
catchments (Norway), Water Air Soil Pollut., 81, 67-91.
Taugbøl, G., H.M. Seip,
and N. Christophersen, 1994. Interactions of organic substances with $Al$ and $H^+$ in soil- and
surface waters: Two equlibrium models and a concept
for statistical testing of models, J. Ecol. Chem., 233-252.
Lillkjendlie,B., D. Kugiumtzis, and N. Christophersen, 1994. Chaotic time series: Part II. System
identification and prediction, Modelling Identification and Control (MIC), 15
(4), 225-243.
Kugiumtzis, D., B. Lillkjendlie, and N.
Christophersen, 1994. Chaotic time series: Part I. Estimation of invariant
properties in state space, Modelling Identification and Control (MIC), 15 (4), 205-224.
Christophersen,
N., C. Neal, and R.P. Hooper, 1993. Modelling the
hydrochemistry of catchments: a challenge for the scientific method, J. Hydrol., 152,
1-12.
Hooper,
R.P. and N. Christophersen, 1992. Predicting episodic
stream acidification in the southeastern United
States: Combining a long-term acidification model and the end-member mixing
concept, Water Resour. Res., 28, 1983-1990.
Easthouse, K. B., J. Mulder, N. Christophersen,
and H.M. Seip, 1992.
Dissolved organic carbonduring variable hydrologival conditions at Birkenes,
southern Norway, Water Resour. Res., 28, 1585-1596.
Christophersen,
N. and R.P. Hooper, 1992. Multivariate analysis of streamwater chemical data: The use of principle component
analysis for the end-member mixing problem, Water Resour.
Res., 28, 99-107.
Mulder, J., M. Pijpers and N. Christophersen,
1991. Water flow paths and the spatial distribution of soils and exchangeable cations in an acid - rain impacted and a pristine catchment in Norway, Water Resour.
Res., 27, 2919-2928.
Neal,
C., J. Mulder, N. Christophersen, M. Neal, D. Waters,
R.C. Ferrier, R. Harriman, R. McMahon, 1990.
Limitations in the understanding of ion-exchange and solubility controls for
acidic Welsh, Scottish, and Norwegian sites, J. Hydrol.
,116, 11 - 23.
Christophersen, N., C. Neal, R.D.
Vogt, J. Esser, and S. Andersen, 1990. Aluminium mobilization in soil and streamwaters at three Norwegian catchments with differences
in acid deposition and site characteristics, Sci.
Tot. Env., 96, 175 - 188.
Christophersen,
N., A. Robson, C. Neal, P.G. Whitehead,
B. Vigerust, and A. Henriksen,
1990. Evidence for long term deterioration in streamwater
chemistry and soil acidification at the Birkenes catchment, southern Norway. J. Hydrol.,
63 - 76.
Hooper,
R.P., N. Christophersen, and N.R.
Peters, 1990. Modelling streamwater chemistry as a
mixture of soil water endmembers - An application to
the Panola experimental catchment,
Georgia, USA, J. Hydrol., 116, 321 - 343.
Christophersen,
N., C. Neal, and R.P. Hooper, R.D. Vogt, and S.
Andersen 1990. Streamwater chemistry as a mixture of
soil water endmembers - Towards developement
of second generation
acidification
models, J. Hydrol., 116, 307 - 320.
Christophersen,
N., R.D. Vogt, C. Neal, H.A. Anderson, R.C. Ferrier, J.D. Miller, and H.M.
Seip, 1990. Controlling mechanisms for streamwater chemistry at the pristine Ingabekken
site in mid Norway: Some implications for acidification models, Water Resour. Res., 26, 59-67.
Mulder, J., N. Christophersen, M. Hauhs,
R.D. Vogt, S.Andersen and D.O. Andersen, 1990. Hydrochemical controls in the Birkenes
catchment as inferred from a rainstorm high in seasalts.
Water
Resour. Res., 26, 611-622.
Christophersen,
N., C. Neal, and J. Mulder 1990. Reversal of stream
acidification at the Birkenes catchment,
southern Norway: Predictions based on potential ANC changes, J. Hydrol. , 116, 77 - 84.
Christophersen,
N. and C. Neal, 1990. Linking hydrological, geochemical, and soil chemical processe on the catchment scale:
An interplay between field work and modelling, Water Resour.
Res., 26,3077-3086.
Vogt,
R.D., H.M. Seip, N.
Christophersen, and S. Andersen, 1989, Assessment of aluminium mobilization and
water pathways at the Birkenes catchment,
southern Norway, Sci. Tot. Env.,
96, 139 - 158.
Lundquist,
D., N. Christophersen, and C. Neal, 1989. Towards developing a new short term
model for the Birkenes catchment
- Lessons learned, J. Hydrol., 116, 78 - 84.
Neal,
C. and N. Christophersen, 1989. Inorganic aluminium - hydrogen ion
relationships for acidified streams; the role of water mixing processes. Sci. Tot. Env., 80, 195 - 203.
Ferrier,
R.C., J.S. Andersen, J.D.
Miller, and N. Christophersen, 1989. Changes in soil and stream hydrochemistry
during periods of spring snowmelt at a pristine site in mid-Norway, Water Air
Soil Pollut, 44, 321-337.
Christophersen,
N. and C. Neal, 1989. A rational approach to the assessment of aluminium
solubility controls in freshwater, Sci. Tot. Env., 84, 91 - 100.
Seip, H.M., D.O.
Andersen, N. Christophersen, T.J. Sullivan and R.D. Vogt, 1989. Variations in
concentrations of aqueous aluminium and other chemical species during
hydrological episodes
at Birkenes, southernmost Norway, J. Hydrol.,
108, 387-405.
Hooper,
R.P., A. Stone, N. Christophersen, E. de Grosbois and H.M. Seip, 1988. Assessing the Birkenes
model of stream acidification using a multisignal
calibration methodology, Water
Resour. Res., 24, 1308-1316.
de Grosbois, E., R.P. Hooper and N.
Christophersen, 1988. A multisignal automatic calibration methodology for hydrochemical models: A case study of the Birkenes model. Water Resour.
Res.,
24,
1299-1307.
Neal,
C., N. Christophersen, R. Neale, C.J.
Smith, P.G. Whitehead and
B. Reynolds, 1988. Chloride in precipitation and streamwater
for the upland catchment of River Severn, Mid-Wales:
Some
consequences for hydrochemical models, Hydrol. Process., 2, 155-165.
Hansteen, I.L., N. Christophersen and S. Langgård, 1987. Surveillance of pregnancies as a means of
detecting environmental and occupational hazards. II Growth criteria including
birth
weight,
length, and head circumference in a newborn population. Hereditas,
107, 205-211.
Wright,
R.F., E. Gjessing, N.
Christophersen, E. Lotse, H.M.
Seip, A. Semb, B. Sletaune, R. Storhaug and K. Wedum, 1986. Project RAIN: Changing acid deposition to
whole catchment. The
first
year of treatment. Water Air Soil Pollut., 30, 47-63.
Whitehead, P.G., C. Neal, S. Seden-Perrington,
N. Christophersen and S. Langan, 1986. A time-series
approach to modelling stream acidity. J.
Hydrol., 85, 281-303.
Seip, H.M., N. Christophersen and S. Rustad, 1986.
Predicted changes in streamwater chemistry
following reduced/increased sulphur deposition using the "Birkenes model". Water Air and Soil Pollut., 31, 239-246.
Reuss, J.O., N. Christophersen and H.M. Seip, 1986. A critique of models for freshwater and soil
acidification. Water Air Soil Pollut., 30, 909-930.
Sullivan,
T.J., N. Christophersen, I.P. Muniz, H.M. Seip and P.D.
Sullivan, 1986. Aqueous aluminium chemistry: Response to episodic increases in
discharge. Nature, 323, 324-327.
Rustad, S., N. Christophersen, H.M. Seip and P.J. Dillon, 1986. Model
for streamwater chemistry of a tributary to HarpLake, Ontario.
Can. J. Fish. Aquat. Sci.,
43, 625-633.
Christophersen,
N., S. Rustad and H.M. Seip, 1984.
Modelling streamwater chemistry with snowmelt,
Phil. Trans. R. Soc. Lond. B 305, 427-439.
Christophersen,
N., L.H. Dymbe, M. Johannessen and H.M. Seip, 1984. A model
for sulphate at Storgama, southern Norway, Ecol.
Model., 21, 35-61.
Christophersen,
N., C. QWvenold, H.M. Seip, and O. Tollan, 1982. Sodium
mobility in a mini-catchment studied with radioactive
tracers and artificial precipitation, Nordic Hydrology, 13, 105-114.
Christophersen,
N., A.O. Stuanes, and R.F.
Wright, 1982. Runoff chemistry at a mini-catchment
watered with "unpolluted" precipitation, Nordic Hydrology, 13,
115-128.
Christophersen,
N., H.M. Seip, and R.F. Wright, 1982. A model for streamwater
chemistry
at Birkenes, Norway, Water Resour.
Res., 18, 977-996.
Christophersen,
N. and R.F. Wright, 1981. Sulfate
budget and a model for sulfate concentrations in streamwater at Birkenes, a small forested
catchment in southernmost Norway, Water Resour. Res., 17, 377-389.
Christophersen,
N., A. Njøs, and H.M. Seip, 1980. Simulation of flow patterns and ion exchange in
soil percolation experimnts - part II Ion - exchange
processes, Water Air Soil Pollut., 14, 159- 170.
Dahl,
J.B., C. Qvenild, O. Tollan,
N. Christophersen, and H.M. Seip,
1979. Methodology of studies on chemical processes in water runoff from rock
and shallow soil cover using radioactice tracers,
Water Air Soil Pollut., 11, 179-190.
Book
chapters
Neal,
C., Robson, A.J., and Christophersen, N., 1997.
Towards coupling hydrological, soil, and weathering processes within a
modelling perspective, In Saether, O.M. and de Caritat, P. (eds.)
Geochemical processes, weathering and groundwater recharge in catchments, pp.
329-380, A.A. Balkema,
Rotterdam.
Seip, H.M., N. Christophersen, J. Mulder, and G. Taugbøl, 1995.
Integrating field work and modelling - the Birkenes
case, In. Trudgill, S. T. (ed.) Solute modelling in catchment
systems, pp. 387-416, J. Wiley, New York.
Christophersen,
N., T.A. Clair, C.T.
Driscoll, D.J. Jeffries, C. Neal, and R. Semkin, 1994. Hydrochemical
studies, In Moldan, B. and Cerny,
J., (eds.) Biogeochemistry of small catchments: A tool for Environmental
Research, SCOPE (Scientific Committee on Problems of the Environment), 51, pp.
285-298.
Stone,
A., N. Christophersen, H.M. Seip,
R.F. Wright, 1990. Predictions of stream
acidification using the Birkenes and MAGIC models, In
Mason, B.J. (ed.), The Surface Waters Acidification
Programme, Cambridge University Press, pp. 495- 499.
Vogt,
R.D., D.O. Andersen, S. Andersen, N. Christophersen,
and J. Mulder, 1990. Streamwater,
soil water chemistry, and water flow paths at Birkenes
during a dry-wet hydrological cycle, In Mason, B.J.
(ed.), The Surface Waters Acidification Programme, Cambridge University Press,
pp. 149-154.
Christophersen,
N., C. Neal, H.M. Seip, and
A. Stone, 1990. Hydrogeochemical models for
simulation of present and future short term changes in stream flow and
chemistry: Development and Status, In Mason, B.J.
(ed.), The Surface Waters Acidification Programme, Cambridge University Press,
pp. 445- 452.
Christophersen,
N., M. Hauhs, J. Mulder, H.M. Seip, and R.D. Vogt, 1990. Hydrogeochemical processes in the Birkenes
catchment, In Mason, B.J.
(ed.), The Surface Waters Acidification Programme, Cambridge University Press,
pp. 97- 106.
Seip, H.M., I.A. Blakar, N. Christophersen, H. Grip, and R.D. Vogt, 1990. Hydrochemical studies in Scandinavia, In Mason, B.J. (ed.), The Surface Waters Acidification Programme,
Cambridge University Press, pp. 19-30.
Seip, H.M., N. Christophersen and S. Rustad, 1987. Changes in streamwater
chemistry and fishery status following reduced sulphur deposition: Tentaive predictions based on the “Birkenes
model”, In Barth, H. (ed.) Reversibility of acidification, Elsevier, London, pp
149-155.
Christophersen,
N., M. Johannessen, and R. Skaane,
1987. Testing a soil-oriented
charge
balance equilibrium model for freshwater acidification, In Barth, H. (ed.)
Reversibility of acidification, Elsevier, London, pp 142-148.
Christophersen,
N., S. Rustad, and H.M. Seip, 1986. Modelling soil water interactions
in
catchments in southern Norway, In Troyanowski, C.
(ed.) Air pollution and plants, Proceedings of the 2nd European Conference on
Chemistry and the Environment, VCH Verlagsgesellschaft, Weinheim,
Germany, pp. 230-235.
Christophersen,
N., 1978. Safety of contraceptive methods, In Walløe,
L. (ed.) Sexuality, family planning and
contraception in Norway, Universitetsforlaget, Oslo,
pp. 123-128 (in Norwegian).
Christophersen,
N., K. Liestøel, and L. Walløe,
1978. Family intentions, family planning and births, In Walløe,
L. (ed.) Sexuality, family planning and contraception in Norway, Universitetsforlaget, Oslo, pp. 113-122 (in Norwegian).
Papers
in refereed proceedings
Dahl, T., O. Lingjærde, N. Christophersen, and T. Ekman,
2005. Local-ICA: Independent component analysis for sources with non-stationary
amplitudes. IEEE Eighth International Symposium on Signal Processing and its
Applications (ISSPA).
Dahl, T.,
N. Christophersen, and D. Gesbert, 2002. BIMA - Blind iterative MIMO
algorithm, Proc. IEEE International Conference on Acoustics,
Speech, and Signal Processing, Orlando, Florida (ICASSP).
Dahl, T., N. Christophersen, and D. Gesbert, 2002. Identification of parallel MIMO channels in wireless communication using power iterations, Proc. IEEE Nordic Signal Processing Conference, Tromsø, Norway.
Gesbert,
D., T. Ekman and N. Christophersen, 2002. Capacity Limits of Dense Palm-Sized MIMO
Proc. IEEE International Globecom Conference, Taipei,
Taiwan.
Bølviken,
E. and N. Christophersen, 1998. Non-linear state estimation by Monte Carlo
filters: A six-dimensional example. Proc. IEEE Conference on Decision and
Control, Tampa, Florida.
Seip, H.M., N. Christophersen and T.J. Sullivan, 1989. Episodic
variations in streamwater aluminium
chemistry at Birkenes, southermost
Norway, Proc. 194th Annual meeting of the American Chemical Society,
New Orleans.
Kolset,
K., B.F. Aschjem, N. Christophersen, A. Heiberg and
B. Vigerust, 1987. Evaluation of some chemical fate
and transport models – A case study on the pollution of the Norrsundet
bay (Sweden), Proc. 4th Europan Symposium
on the Aquatic Environment, EU COST 641.
Christophersen,
N. and C. Neal, 1987. Some results important for further development of hydrochemical models describing freshwater acidification,
Proc. GEOMON – International workshop on Geochemistrey and
Monitoring in Representative Catchments, Geological Survey, Prague.
Christophersen,
N., S. Kjærnsrød and A. Rohde, 1985. Preliminary
evaluation of flow patterns in the Birkenes catchment using natural 18O as a tracer, Proc.
Hydrological and Hydrogeochemical Mechanisms and Model Approaches to the
Acidification of Ecological Systems, International Hydrological Programme, Uppsala.
Christophersen,
N. and H.M. Seip, 1983.
Mechanisms and prognosis of freshwater acidification: A modelling
approach, Proc. Environment ´82, Swedish Environment Protection Agency (SNV), Stockholm.
Christophersen,
N. and R.F. Wright, 1980. Sulphate
at Birkenes, a small forested catchment
in southernmost Norway, Proc. Ecological Impact of Acid Precipitation, SNSF-project, Norwegian Institute for Water
Research.
Dymbe, L.H. and N. Christophersen, 1980. Modelling
sulphate concentrations in streamwater
at Storgama, southern Norway, Proc. Ecological Impact
of Acid Precipitation, SNSF-project,
Norwegian Institute for Water Research.
Christophersen,
N., K. Brustad, J.B.Dahl,
T. Gulliksen, A. Njøs, C. Qvenild, H.M.Seip and O. Tollan, 1980. Water residence distributions, Proc.
Ecological Impact of Acid Precipitation, SNSF-project, Norwegian Institute for Water Research.
Dahl, J.B.,
C. Qvenild, O. Tollan, N.
Christophersen and H.M.Seip, 1980. Use of radioactive
tracers to study runoff and soil/water interactions in natural mini-catchments,
Proc. Ecological Impact of Acid Precipitation, SNSF-project, Norwegian Institute for Water Research.
Hisdal,
E., N. Christophersen, T. Ericson, A. Løkketangen and
S. Vestøl, 1976. Structural recognition of
handwriting, Proc. IEEE Third International Conference on Pattern Recognition,
Coronado, California.
Christophersen,
N. and T. Lange –Nielsen, 1973. Construction of suboptimal Kalman
filters by pattern search, Proc. 17th meeting AGARD
Guidance and Control Panel, Conference Proc. 137, NATO.
Other scientific publications (incl. research
reports and preprints)
Gesbert,
D. and N. Christophersen, 2002. Space: The final (wireless) frontier, Norsignalet, 4 (1), 4-8
Kugiumtzis,
D., and N. Christophersen, 1997. State space reconstruction: Method of delays
vs. singular spectrum approach, Research report 236, Department of informatics,
University of Oslo, 11 pp.
Bølviken, E., P.J. Acklam, N. Christophersen,
and J.M. Størdal, 1997.
Monte Carlo filters for non-linear state estimation, Statistical Research
Report, No. 14, Department of mathematics, University of Oslo, 22 pp.
Christophersen N, Bølviken E and Snipen L., 1996. Strategies for modelling biological time
series, Workshop on Non-linear Methods for Analysis of Biological Time Series:
Delineating the possible from the impossible, Rosendal,
Norway, 6-8 September.
Bjerknes, R., N.
Christophersen, and L.G. Snipen,
1993. The complete stability domain of a nonlinear differential equation: The
flower and the bees, Research report 180, Department of informatics, University
of Oslo, 21 pp.
Christophersen, N. and P.G: Whitehead, 1987
(eds.). Proc. Surface Water Acidification Programme
(SWAP) modelling
workshop, Institute of Hydrology Report, 40 pp.
Sullivan, T.J., N. Christophersen, R.P. Hooper,
H.M. Seip, I.P. Muniz, P.D.Sullivan and R.D.
Vogt, 1987. Episodic variation in streamwater
chemistry at Birkenes, southermost
Norway: Evidence for the importance of flow paths, Proc. International
Symposium on Acidification and Water pathways, Norwegian Hydrological
Committee, Oslo.
Sullivan, T.J., N. Christophersen and I.P:
Muniz, 1987. Soil and streamwater chemistry during
snowmelt at the Birkenes catchment,
southermost Norway, Centre for Industrial Research,
850701-1, 27 pp
Christophersen, N., 1987. Modelling the effects
of acid deposition: Status and trends, Proc. Surface Water Acidification Programme (SWAP), Mid-term conference, Bergen.
Reuss, J.O.,
N. Christophersen and H.M.Seip, 1986. A critique of
models for freshwater and soil acidification, Centre for Industrial Research,
850137-1, 43 pp
Christophersen, N. and P.G: Whitehead, 1985
(eds.). SWAP (Surface Water Acidification Programme),
Modelling workshop report, Centre for Industrial
Research, SI-publ. 2042, 25 pp.
Christophersen, N., 1985. Sur nedbør – årsaker og virkninger
(Acid precipitation – causes and effects), Proc. Effects of Acid Deposition,
Norwegian Forestry Association/Norwegian Ministry of Environment, Fevik, Norway.
Christophersen,
N., A. Heiberg, K. Kveseth and E. Næss-Ulseth,
1984. Forurensningssituasjonen
i Mo i Rana – Eksempel på beslutningsanalyse av tiltak mot forurensninger (Environmental pollution in Mo i Rana – An example
using decision analysis techniques), Centre for Industrial Research, 830123-1, 44 pp.
Christophersen, N., 1983. Freshwater acidification – A modelling approach, Dr. philos.
thesis, University of Oslo.
Christophersen, N., 1983. Betydningen av lokale svovelutslipp
for kvaliteten av overflatevann ved Oxeløsund (Importance of local sulphur
emissions for the freshwater quality near Oxeløsund),
Centre for Industrial Research, 821107-1, 18 pp.
Christophersen, N. and T. Gulliksen, 1981. An
analysis of hydrologic reservoir models used for water quality modelling, Report No 10, Norwegian Hydrological Committee,
38 pp.
Seip, H.M.,
G. Abrahamsen, N. Christophersen, E.T. Gjessing and A.O. Stuanes, 1980.
Snowmelt and meltwater chemistry in mini-catchments, SNSF-project, Norwegian Institute for Water Research, IR 53/80, 51 pp.
Brustad, K., N.
Christophersen, A. Njøs and H.M.
Seip, 1979. Simulation of flow patterns and
ion-exchange relationships in a series of soil percolation experiments, SNSF-project, Norwegian Institute for Water Research, TN
41/79, 89 pp.
Dahl, J.B., N. Christophersen, C. Qvenild, H.M. Seip and O. Tollan, 1978. Omsetting av kalsium og
sulfat i små felter undersøkt
ved hjelp av radioaktive tracere (Assessing the movement of calcium and sulphate in mini-catchments using radioactive tracers), SNSF-project, Norwegian Institute for Water Research, TN
42/78, 61 pp.
Christophersen, N. and O. Ørpen, 1976. Detaljsimuleing av referanseplattformen med PICO og omegn (Detailed simulation of the reference platform with
PICO and external signals), Norwegian Defense Research Establishment, TN E-781, 88 pp.
Christophersen, N., 1975. Referanseplattformen
– oppretting og navigasjon (The reference platform – alignment and
navigation), Norwegian
Defense Research Establishment, TN E-708, 62 pp.
Christophersen, N., 1975. Oppdatering av INS ved hjelp
av flere sensorer (Updating an INS using several sensors), Norwegian Defense Research
Establishment, TN E-691, 13 pp.
Christophersen, N., 1975. Optimal and suboptimal aided inertial
navigation – part II, Norwegian
Defense Research Establishement, TN E-690, 77 pp.
Christophersen, N., 1975. Evaluering av forenklet Kalman
filter i referanseplattformen
ved Monte Carlo simuleringer
(Evaluation of simplified Kalman filters in the
reference platform using Monte Carlo simulations), Norwegian Defense Research Establishement,
TN E-689, 39 pp.
Christophersen, N., 1974. Undersøkelse av en Schuleravstemt og en selvinnrettende plattform med Kalman filter
(Investigation of a Schulertuned
and a selfaligning platform with Kalman
filters), Norwegian
Defense Research Establishement, TN E-633, 37 pp.
Christophersen, N. and O. Ørpen, 1974. Bruk av mikroprosessor
i en regnekrevende sanntidsanvendelse (Using a micro processor in a
computationally demanding real time application), Course Micro processors and
their use, Norwegian Civil Engineer Association.
Christophersen, N., 1972. Enkel optimal tilbakekobling med Kalman filter og en deterministisk regulator (A
simple optimal fedback with a Kalman
filter and a deterministic regulator), Servo meeting, Trondheim, Norway.
Christophersen, N., 1972. Optimal and suboptimal aided inertial
navigation, Norwegian
Defense Research Establishement, IR
E-200, 99 pp.
Christophersen, N., 1970. An introductory analysis of a gyrocompassing inertial navigation system, Norwegian Defense Research Establishement, TN E-310, 41 pp.
Christophersen,
N., 1969. Library functions for SM-3, Norwegian Defense Research Establishement, TN E-239, 36 pp.
Other (lecture notes, articles in newspapers, etc.)
Christophersen, N.,
2002. Digital Dignalbehandling og Bildeanalyse (DSB) ved UiO, Norsignalet,
4 (1), 3-4.
Christophersen, N og
J. Trulsen, 2002. Naturvitenskap må inn i ex.phil. (Science has a place
in examen philosophicum), Aftenposten, 23. februar.
Norum, K.A., N. Christophersen,,
A. Elverhøi, J. Grue og Uggerud,
E., 2000. Hånd i hånd med næringslivet (Hand in hand with industry), Dagens
Næringsliv, 18/19 mars.
Lindgjærde, O.C. and N. Christophersen, 1998. Regularization principles – Solving
ill-posed inverse problems, Lecture notes to IN INVPAR,
Department of informatics, 79 pp.
Bølviken,
B., N. Christophersen, and G. Storvik, 1998. Linear
dynamical models, Kalman filtering and statistics,
Lecture notes to IN-ST 259, Department of informatics, 163 pp.
Sjøberg, D. og N.
Christophersen, 1996. Den menneskefiendtlige informasjonsteknologien og andre
myter (The inhuman information
technology and other myths), Schola, Nr. 1, pp. 45-47.
Sjøberg, D. og N.
Christophersen, 1995. Bør PC markedsførere spises til aftens (Should PC vendors be eaten for supper), kronikk Dagladet
19. desember 1995.
Christophersen, N.
og A.M. Bruaset, 1994. En enkel forsuringsmodell
(A simple acidification model), Lecture notes IN 104, Department of
informatics, Kompendium 54, 27 pp.
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