@Phdthesis{CitationKey,
author = {Kr\"{a}mer, Jan},
title = {{Tariffication, Prioritization and Regulation: Eight Essays on
Telecommunications Markets}},
school = {Karlsruhe Institute of Technology},
year = {2013},
type = {Habilitation thesis}}

					

@Proceedings{CitationKey,
title = {{Network Neutrality and Open Access}},
year = {2011},
editor = {Spiecker gen. D\"{o}hmann, Indra and Kr\"{a}mer, Jan},
address = {Baden Baden},
publisher = {Nomos Publishing},
note = {ISBN 978-3-8329-6618-8, 214 p},
url = {http://www.amazon.de/dp/3832966188},
abstract = {The principle of Network Neutrality prescribes that all data packets
that are being sent through the Internet must be treated equally with respect
to their origin, destination and content. It has recently achieved much attention
by policymakers in the US and Europe and is debated very controversially. This
book seeks to advance this debate by providing a scientific and unbiased view
on Network Neutrality, and the related issue of Open Access as policy instruments
to counteract the anticipated scarcity of telecommunications infrastructure.
The book comprises articles by leading international legal and economic scholars
as well as by policymakers on the possible effects of Network Neutrality and
Open Access regulation and thus offers a holistic and interdisciplinary viewpoint
on these issues.}}

					

@Proceedings{CitationKey,
title = {{Information Management and Market Engineering: Vol. II}},
year = {2010},
editor = {Dreier, Thomas and Kr\"{a}mer, Jan and Studer, Rudi and Weinhardt,
Christof},
number = {11},
series = {Studies on eOrganisation and Market Engineering},
address = {Karlsruhe},
publisher = {KIT Scientific Publishing},
note = {260 p., ISBN: 978-3-86644-589-5},
url = {http://www.amazon.de/dp/386644589X},
abstract = {The research program "Information Management and Market Engineering"
focuses on the analysis and the design of electronic markets. Taking a holistic
view of the conceptualization and realization of solutions, the research
integrates the disciplines business administration, economics, computer science,
and law. Topics of interest range from the implementation, quality assurance,
and further development of electronic markets to their integration into business
processes, innovative business models, and legal frameworks.



This second volume not only collects the advancements of the Graduate School
"Information Management and Market Engineering" at the Karlsruhe Institute of
Technology, which is funded by the Deutsche Forschungsgemeinschaft (German
Research Foundation), since the first volume of this book, but also points at
new research fields that have recently been explored.}}

					

@Proceedings{CitationKey,
title = {{Communications Regulation in the Age of Digital Convergence: Legal
and Economic Perspectives}},
year = {2009},
editor = {Kr\"{a}mer, Jan and Seifert, Stefan},
address = {Karlsruhe},
publisher = {Universit\"{a}tsverlag Karlsruhe},
note = {110 p., ISBN 978-3-86644-387-7},
url = {http://www.amazon.de/dp/3866443870},
abstract = {The communications sector is currently undergoing a tremendous
transformation. In particular, the changes driven by the digitalization and
convergence of communications networks and devices have a significant impact
on society and culture as well as economic growth and wealth. The editors of
this book have brought together a distinguished panel of regulators as well
as lawyers and economists from both academia and industry to present their
insights on the convergence phenomenon. The contributions cover a great deal
of the relevant topics in communications regulation, such as technological and
network neutrality, distribution of the digital dividend, and incentives for
investment and innovation. They highlight the fact that the technological
advancements have caused major changes in the regulatory frameworks of Europe
and the US and continue to pose regulatory challenges with respect to ensuring
a level playing field for all competitors. However, until today also many
regulatory legacies of the analog age have remained unchanged and need
reconsideration in the age of digital convergence.}}

					

@Book{CitationKey,
title = {{Bundling Telecommunications Services: Competitive Strategies for
Converging Markets}},
publisher = {Universit\"{a}tsverlag Karlsruhe},
year = {2009},
author = {Kr\"{a}mer, Jan},
address = {Karlsruhe},
note = {174 p., ISBN 978-3-86644-377-8},
url = {http://www.amazon.de/dp/3866443773},
abstract = {With the advent of digital convergence, incumbent telephone and
cable companies have begun to offer their services, such as voice telephony,
Internet and TV in so-called triple play packages. While carefully recognizing
the technological, legal and economic framework of the fixed-line
telecommunications industry, this book investigates whether bundling is indeed
a profitable pricing strategy for the firms and if it can possibly facilitate
the leverage of market power into neighboring markets. In contrast to previous
work on bundling, a symmetric duopoly market structure is considered, with two
firms having market power in their respective home markets, but without any
clear ex-ante advantage for either firm on the converged market.

This book also serves as a basic introduction into the technological, economic
and regulatory concepts of communications as well as into the theory of
bundling.}}

					

@Book{CitationKey,
title = {{The Conference Scheduling Problem}},
publisher = {VDM Verlag},
year = {2009},
author = {Kr\"{a}mer, Jan},
address = {Saarbr\"{u}cken},
note = {160 p., ISBN 978-3-639-15876-2},
url = {http://www.amazon.de/dp/3639158768},
abstract = {This book studies exact solution procedures for the so-called
Conference Scheduling Problem (CSP), which seeks to minimize the duration of
a conference, where some of the activities cannot be held concurrently. The
CSP corresponds to non-preemptive scheduling of independent activities with
dedicated resources and constitutes a special case within the more general
Resource Constraint Project Scheduling Problem (RCPSP) as well as the machine
scheduling framework, and as such it is NP-hard. The core characteristics of
CSP are commonly encountered in problems of different domains and therefore
the problem is of high practical relevance. The book focuses on the analysis
and comparison of graph-based solution procedures, which operate on a constrained
graph that is derived from the confliciting acitivies to be scheduled. In
particular Interval Coloring and Comparability Graph Augmentation are considered.
An emphasis is put on the investigation of variations of the latter procedure,
which exploits the structure of the constraint graph and is therefore robust
to variations in the activity durations.}}

					

@Article{CitationKey,
author = {Horstmann, Niklas and Kr\"{a}mer, Jan},
title = {{Price discrimination or uniform pricing: Which colludes more?}},
journal = {Economics Letters},
year = {2013},
doi = {10.1016/j.econlet.2013.05.011}}

					

@Article{CitationKey,
author = {Kr\"{a}mer, Jan and Wiewiorra, Lukas and Weinhardt, Christof},
title = {{Net neutrality: A progress report}},
journal = {Telecommunications Policy},
year = {2013},
doi = {10.1016/j.telpol.2012.08.005},
abstract = {This paper is intended as an introduction to the debate on net
neutrality and as a progress report on the growing body of academic literature
on this issue. Different non-net neutrality scenarios are discussed and structured
along the two dimensions of network and pricing regime. With this approach,
the consensus on the benefits of a deviation from the status quo as well as
the concerns that are unique to certain non-net neutrality scenarios can be
identified. Moreover, a framework for policy decisions is derived and it is
discussed how the concept of neutrality extends to other parts of the Internet
ecosystem.}}

					

@Article{CitationKey,
author = {Elsner, Helmuth and Kr\"{a}mer, Jan},
title = {{Managing Corporate Portal Usage with Recommender Systems}},
journal = {Business & Information Systems Engineering (BISE)},
year = {2013},
note = {Appears also in German as "Nutzungsmanagement von Unternehmensportalen
mit Hilfe von Empfehlungssystemen" in WIRTSCHAFTSINFORMATIK}}

					

@Article{CitationKey,
author = {Adam, Marc T. P. and Kr\"{a}mer, Jan and Weinhardt, Christof},
title = {{Excitement up! Price Down! Measuring Emotions in Dutch Auctions}},
journal = {International Journal of Electronic Commerce},
year = {2012–13},
volume = {17},
pages = {7-39},
number = {2},
doi = {10.2753/JEC1086-4415170201},
abstract = {Recently Internet auction sites have begun to compete in emotions
by advertising the fun and excitement that bidders may experience during auction
participation. The implicit conjecture inherent in these advertisements is that
consumers derive a hedonic value from auction participation that makes exciting
auctions more attractive and possibly induces bidders to stay active longer
in the auction. We test this conjecture in a controlled economic laboratory
experiment in which we also measure bidders’ physiological arousal in terms
of heart rate and skin conductivity as proxies for their excitement during auction
participation. In particular, we conduct a series of descending price (Dutch)
auctions with different clock speeds and find that in fast Dutch auctions bidders
(i) are more excited and (ii) stay longer in the bidding process. Moreover,
the unpleasant event of losing a Dutch auction is experienced more strongly
than the rewarding event of winning. As our results show that bidders’ excitement
is directly reflected in final prices, Internet auction sites should carefully
consider how the emotions elicited on their platforms affect bidding behavior.}}

					

@Article{CitationKey,
author = {Kr\"{a}mer, Jan and Wiewiorra, Lukas},
title = {{Network Neutrality and Congestion Sensitive Content Providers:
Implications for Content Variety, Broadband Investment and Regulation}},
journal = {Information Systems Research},
year = {2012},
volume = {23},
pages = {1303--1321},
number = {4},
month = {December},
doi = {10.1287/isre.1120.0420},
abstract = {We study departures from network neutrality through implementing
a Quality of Service tiering regime in which an ISP charges for prioritization
on a non-discriminatory basis. We find that Quality of Service tiering may be
more efficient in the short run, because it better allocates the existing network
capacity, and in the long run, because it provides higher investment incentives
due to the increased demand for priority services by the entry of new congestion
sensitive content providers. Which network regime is the most efficient depends
on the distribution of congestion sensitivity among content providers, but a
guideline is that the regime that provides higher incentives for infrastructure
investments is more efficient in the long run.}}

					

@Article{CitationKey,
author = {Kr\"{a}mer, Jan and Wiewiorra, Lukas},
title = {{Beyond the flat rate bias: The flexibility effect in tariff choice}},
journal = {Telecommunications Policy},
year = {2012},
volume = {36},
pages = {29-39},
number = {1},
doi = {10.1016/j.telpol.2011.11.015},
url = {http://www.sciencedirect.com/science/article/pii/S0308596111002084},
abstract = {Flat rates are a prominent pricing scheme for telecommunications
services and are often preferred by consumers although average costs would be
lower in an alternative usage-based tariff. Reasons are that flat rates protect
against unexpectedly high costs (insurance effect), are more likely to be chosen
if actual usage is overestimated (overestimation effect), and prevent any
disutility that is associated with the immediate perception of usage marginal
costs  (taximeter effect). This study complements the literature on tariff biases
by highlighting that a lack of tariff flexibility is a major impediment to
choosing a flat rate: Empirical support for this flexibility effect is found,
while, at the same time, the insurance and overestimation effect that run in
favor of flat rates are confirmed. Finally, the managerial implications of the
findings for the introduction of the new cost cap tariff are discussed. The
hybrid cost cap tariff can combine the flexibility and the insurance property,
and may, therefore, exert a cost cap bias on consumers.}}

					

@Article{CitationKey,
author = {Adam, Marc T. P. and Kr\"{a}mer, Jan and J\"{a}hnig, Caroline and
Seifert, Stefan and Weinhardt, Christof},
title = {{Understanding Auction Fever: A Framework for Emotional Bidding}},
journal = {Electronic Markets},
year = {2011},
volume = {21},
pages = {197-207},
number = {3},
doi = {http://dx.doi.org/10.1007/s12525-011-0068-9},
url = {http://www.springerlink.com/content/e0451724342632lq},
abstract = {Auction fever is a multifaceted phenomenon that is frequently observed
in both traditional and Internet auctions. In order to gain a better understanding
of its causes, we develop a conceptual framework to analyze emotions in auctions,
which is based on an exhaustive literature review. The framework integrates
rational calculus with emotional aspects and suggests that emotional processing
is triggered at three different stages of an auction: First, the economic
environment can affect a bidder’s level of perceived competition and thus
influence the bidding strategy prior to the auction. Second, auction events
may have ramifications on the bidder's emotional state during the auction due
to previous investments or perceived ownership. Third, past auction outcomes
may impact future bidding behavior through emotions such as the joy of winning
or loser regret. Auction fever, eventually, is a phenomenon that results from
the interplay of these emotional processes and causes a bidder to deviate from
an initially chosen bidding strategy.}}

					

@Article{CitationKey,
author = {Kr\"{a}mer, Jan},
title = {{Bundling Vertically Differentiated Communications Services to Leverage
Market Power}},
journal = {info: The journal for policy, regulation and strategy for
telecommunications, Information and Media},
year = {2009},
volume = {11},
pages = {64-74},
number = {3},
month = {May},
doi = {10.1108/14636690910954980},
url = {http://www.emeraldinsight.com/10.1108/14636690910954980},
abstract = {Purpose – Despite Digital Convergence, in many countries the former
telco monopolist remains to hold significant market power in its home market
for telecommunication services. I investigate whether and how bundling services
may achieve leverage of market power from the telco's home to a secondary service
market (e.g. video broadcasting).



Design/methodology/approach – To this extend I consider a formal game-theoretic
model where the telco firm holds a monopoly in the market for telecommunications
services, while competing with a cable firm in the market for video broadcasting
services. Services may differ in quality. For the firms, the provision of
high-quality services is more costly than the provision of low-quality services.
Conversely, consumers have a greater reservation price for higher service
qualities. Therefore firms face a trade off between revenues and cost when
selecting the optimal service quality.



Findings – The model shows that the telco firm can achieve market power leverage
by bundling its services, which therefore is more profitable than offering each
service separately. In particular, the quality leverage mechanism is highlighted,
which reveals that bundling alters the optimal service quality choice of the
competitors favorably.



Research limitations/implications – Like every game-theoretic model, the present
model rests on formal assumptions representing stylized facts. Future research
should try back these by empirical evidence. 



Practical implications – The paper reveals how bundling may be employed as a
strategic weapon in order to increase profits in the converging communications
market.



Originality/value – The paper shows that bundling communications services can
not only have significant ramifications for the quality of these services, but
also for the competition in industry.



Keywords: Telecommunications Industry, Digital Communications Systems, Competitive
Strategy, Pricing, Services, Game-Theory}}

					

@Inproceedings{CitationKey,
author = {Dalen, Anders and Kr\"{a}mer, Jan and Weinhardt, Christof},
title = {{Determining the optimal level of information granularity for efficient
energy consumption decisions: Experimental evidence}},
booktitle = {Proceedings of the 21st European Conference on Information Systems
(ECIS 2013)},
year = {2013},
address = {Utrecht, Netherlands}}

					

@Inproceedings{CitationKey,
author = {Astor, Philipp J. and Adam, Marc T. P. and Kr\"{a}mer, Jan},
title = {{Influence of emotional pictures on bidding behavior}},
booktitle = {2012 NeuroPsychoEconomics Conference Proceedings},
year = {2012},
address = {Rotterdam, Netherlands},
pages = {18},
editor = {Smidts, Ale and Sanfey, Alan and Reimann, Martin and Schilke, Oliver},
url =
{http://www.jnpe.org/upload/pdf/2012_NeuroPsychoEconomics_Conference_Proceedings.pdf}}

					

@Inproceedings{CitationKey,
author = {Ilg, Jens and Flath, Christoph and Kr\"{a}mer, Jan},
title = {{A Note on the Economics of Metered Grid Pricing}},
booktitle = {Proceedings of the 9th International Conference on the European
Energy Market (EEM)},
year = {2012},
address = {Florence, Italy, 10-12 May 2012},
pages = {1-6},
publisher = {IEEE},
note = {ISBN 978-1-4673-0832-8},
abstract = {Imbalances in generation and demand locality in the German power
market give rise to seemingly unfair grid cost allocations: few customers in
wind-rich north-east Germany pay a major share of the costs of transmitting
power to customers in the south. This development has prompted demands for billing
the extend of grid usage - i.e., a customer's costs should be lower when procuring
`local' power than in the case of distant power. We call this a `metered' grid
costs approach as opposed to the standard global levy. Using an economic model
we find that such metered grid costs may increase total welfare by inducing
higher cost efficiency. However, they will typically also give rise to
significantly higher consumer costs as generators may leverage grid costs as
differentiation devices to enhance their profits.}}

					

@Inproceedings{CitationKey,
author = {Adam, Marc T. P. and Gamer, Matthias and Kr\"{a}mer, Jan and Weinhardt,
Christof},
title = {{Measuring Emotions in Electronic Markets}},
booktitle = {Proceedings of the International Conference on Information Systems
(ICIS)},
year = {2011},
address = {Shanghai, China},
pages = {1-19},
publisher = {Association of Information Systems},
note = {ISBN 978-0-615-55907-0},
url = {http://aisel.aisnet.org/icis2011/proceedings/breakthroughideas/1}}

					

@Inproceedings{CitationKey,
author = {Mazarakis, Athanasios and Kr\"{a}mer, Jan},
title = {{Feedbackmechanismen zur Steigerung der Beteiligung im Web 2.0 –
Ergebnisse einer Feldstudie zu Vorlesungswikis}},
booktitle = {Interaktive Kulturen - Workshop-Band},
year = {2010},
address = {Duisburg, Germany, 12-15 September 2010},
pages = {187-192},
editor = {Schroeder, Ulrik},
series = {Proceedings der Workshops der DeLFI 2010 - Die 8. E-Learning Fachtagung
Informatik der Gesellschaft f\"{u}r Informatik e. V.},
month = {September},
publisher = {Logos Verlag Berlin},
note = {ISBN 978-3-8325-2578-1},
abstract = {Wir untersuchen den Einfluss sogenannter Feedbackmechanismen auf
die Beteiligung im Web 2.0 Kontext. In einer explorativen Studie wurden zwanzig
Studierende bei der Registrierung f\"{u}r ein Vorlesungswiki zuf\"{a}llig,
entweder der Experimentalbedingung (Feedback nach jedem Beitrag) oder der
Kontrollbedin-gung (ohne Feedback) zugewiesen. Zus\"{a}tzlich wurden die
Pers\"{o}nlichkeitseigen-schaften des NEO-FFI Fragebogens abgefragt, wie auch
die psychologischen Grundbed\"{u}rfnisse Autonomie, Kompetenz und soziale
Eingebundenheit. Die Er-gebnisse zeigen einen Anstieg der Beteiligung am Wiki
in der Experimentalbedin-gung (mit Feedback).}}

					

@Inproceedings{CitationKey,
author = {Seifert, Stefan and Kr\"{a}mer, Jan and Mazarakis, Athanasios},
title = {{Anreize zur Nutzung von Wikis in der Hochschullehre - Ergebnisse eines
Pilotprojekts}},
booktitle = {Mensch & Computer 2010},
year = {2010},
address = {Duisburg, Germany},
pages = {179–188},
editor = {Ziegler, J\"{u}rgen and Schmidt, Albrecht},
publisher = {Oldenbourg Wissenschaftsverlag, M\"{u}nchen},
note = {ISBN 978-3-486-70408-2},
abstract = {In einer Pilotstudie an der Universit\"{a}t Karlsruhe wurden
Wiki-Systeme in die Hochschullehre integriert, mit dem Ziel die Studierenden
schon w\"{a}hrend des Semesters zu einer aktiven Auseinandersetzung mit dem
Lehrstoff zu animieren. In dieser Arbeit werden die wesentlichen Erkenntnisse
der Studie vorgestellt, insbesondere im Hinblick auf die Auswirkungen
verschiedener Nutzungsanreize auf die studentische Beteiligung in
vorlesungsbegleitenden Wikis. In der Pilotstudie mit drei unterschiedlichen
Lehrveranstaltungen lassen sich beachtliche Unterschiede hinsichtlich des
studentischen

Engagements aufgrund unterschiedlicher Anreizstrukturen beobachten. Es wird
ebenso diskutiert inwieweit sich die Erkenntnisse der Studie auf andere
Lehrveranstaltungen \"{u}bertragen lassen und welche Potenziale f\"{u}r die
Hochschullehre damit verbunden sind.}}

					

@Inproceedings{CitationKey,
author = {Kr\"{a}mer, Jan and Wiewiorra, Lukas},
title = {{The Taxi Meter Effect: An Experimental Approach}},
booktitle = {Group Decision and Negotiation 2010},
year = {2010},
address = {Delft, the Netherlands},
pages = {228-231},
editor = {de Vreede, Gert-Jan},
month = {21-23 June},
publisher = {University of Nebraska},
note = {ISBN: 978-9-056382-36-0}}

					

@Inproceedings{CitationKey,
author = {Kr\"{a}mer, Jan; Wiewiorra, Lukas},
title = {{Consumer Perception of Mobile Telephony Tariffs with Cost Caps}},
booktitle = {Proceedings of 9th Conference on Telecommunications, Internet and
Media Techno Economics (CTTE)},
year = {2010},
address = {Ghent, Belgium, 7-9 June 2010},
pages = {1-8},
publisher = {IEEE},
note = {ISBN 978-1-4244-7988-7},
doi = {http://dx.doi.org/10.1109/CTTE.2010.5557703},
abstract = {In this article we provide a seminal academic investigation of mobile
telephony consumers' perception of the recently introduced cost cap tariff in
comparison to corresponding pay-per-use and flatrate calling plans. Previous
studies have identified several psychological effects through which consumers
are believed to be biased towards flatrate plans. However, flatrate plans also
limit customers' tariff flexibility in months of low usage. Cost cap tariffs
are a hybrid between pay-per-use and flatrate plans and can offer cost insurance
while maintaining flexibility. In particular, we provide evidence from a survey
among 214 German university students that flexibility, cost insurance and the
so-called taximeter effect are the main drivers behind cost cap tariff choice.
Furthermore, we show that the insurance and taximeter effects are distinct if
evaluated within a flatrate or cost cap tariff framework. Finally, based on
our results we also comment on the profitability of cost cap plans from a
strategic management perspective.}}

					

@Inproceedings{CitationKey,
author = {Elsner, Helmuth and Kr\"{a}mer, Jan},
title = {{Einsatz von Recommender Systemen zum Management von
Unternehmensportalen}},
booktitle = {Multikonferenz Wirtschafsinformatik 2010},
year = {2010},
address = {G\"{o}ttingen, Germany, 23 - 25 February 2010},
pages = {1819-1830},
editor = {Schumann, Matthias and Kolbe, Lutz and Breitner, Michael and Friedrichs,
Arne},
publisher = {Universit\"{a}tsverlag G\"{o}ttingen},
note = {ISBN 978-3-941875-31-9},
url = {http://webdoc.sub.gwdg.de/univerlag/2010/mkwi},
abstract = {Unternehmensportale stellen eine weltweit zug\"{a}ngliche Plattform
zur Unterneh-menskommunikation bereit. Portale der vierten Generation bieten
heute nicht nur Wissensmanagement- und Kollaborationsfunktionalit\"{a}ten an
(Terra und Gorden, S. 1-419; Benbya et al. 2004, S. 201-22), sondern k\"{o}nnen
durch intelligente Dienste auch komplexe Gesch\"{a}ftsprozesse unterst\"{u}tzen
und koordinieren (Dias 2001, S. 274-279; Murray 1999). White spricht in diesem
Zusammenhang von einer Entwicklung hin zu „Enterprise Application Suites“ (2003,
S. 2). Die M\"{o}glichkeiten, die ein Portal in Bezug auf die Unterst\"{u}tzung
verschiedenster Unternehmensprozesse bieten kann, sind also sehr vielf\"{a}ltig
und f\"{u}hren in der Folge zu einem stetigen Wachstum des Portals in Bezug
auf die Komplexit\"{a}t und Anzahl der Dienste, sowie der Nutzer. Das Management
des Portalwachstums und seiner Folgen stellt daher eine zentrale Herausforderung
beim Einsatz von Unternehmensportalen der vierten Generation dar. Explizite
L\"{o}sungsans\"{a}tze zur Bew\"{a}ltigung dieser Problematik finden sich bisher
nicht in der Literatur, die lediglich die M\"{o}glichkeiten des Portalkonzepts
in Unternehmen hervorhebt. Im Gegensatz zu Internetportalen verfolgen
Unternehmensportale kein eigenes Gesch\"{a}ftsmodell, sondern unterst\"{u}tzten
Unternehmen in der Verfolgung ihres Gesch\"{a}ftsmodells. Dieser fundamentale
Unterschied f\"{u}hrt auch zu anderen Anforderungen an das jeweilige
Portalmanagement. Die zentrale Herausforderung des Portalmanagements liegt darin,
Mitarbeiter effektiv bei der Nutzung des Portals zu unterst\"{u}tzen, wobei
das stetige Wachstum besonders ber\"{u}cksichtigt werden muss. Einerseits sollen
Mitarbeiter auf die ihnen bekannten Dienste weiter zugreifen k\"{o}nnen.
Andererseits kann das Potenzial des Portals aber nur entfaltet werden wenn andere
relevante Dienste auch wahrge-nommen werden und zu deren Nutzung angeregt wird.

Um dieses Ziel zu erreichen wird der Einsatz eines Recommender-Systems, welches
spezielle auf den Einsatz in Unternehmensportalen zugeschnitten ist, 
vorgeschlagen. Wichtige Voraussetzungen f\"{u}r die Wahl eines geeigneten
Recommender-Ansatzes sind insbesondere, dass es impraktikabel oder
uner-w\"{u}nscht ist (i) alle Dienste des Portals vollst\"{a}ndig semantisch
zu beschreiben, (ii) das Nutzungsverhalten und Arbeitsprofil jedes Nutzers
vollst\"{a}ndig zu erfassen. Daher k\"{o}nnen nur solche Recommender angewendet
werden, die das Nutzungsverhalten der Mitarbeiter analysieren und daraus
Empfehlungen ableiten. Diese Eigenschaften bef\"{u}rworten die Wahl des
Collaborative Filtering Ansatzes (Goldberg 1992; Resnick et al. 1994)
gegen\"{u}ber dem des Content-Based Filtering (Adomavicius und Tuzhilin 2005).
Bei den Collaborative Filtering Algorithmen sind wieder die memory-based
Algorithmen gegen\"{u}ber den memory-based Algorithmen vorzuziehen, da letztere
nur auf Grund ihrer Skalierbarkeit Vorteile bringen (Breese et al. 1998; Herlocker
et al. 2004). Diese spielt jedoch bei Unternehmensportalen auf Grund der
verh\"{a}ltnism\"{a}\ssig geringen Zahl von Nutzern und Objekten eine
untergeordnete Rolle. Im Weiteren wird auch diskutiert, welche weiteren
Designentscheidungen des Recommender-Systems im konkreten Unternehmenskontext
getroffen werden m\"{u}ssen und wie diese evaluiert werden k\"{o}nnen. Hierzu
geh\"{o}rt unter anderem die Wahl der geeigneten Methodik zur Berechnung der
\"{A}hnlichkeit zwischen Nutzern, das Verfahren zur impliziten Berechnung der
Ratings f\"{u}r Dienste und die Art der Anzeige der Empfehlungen.}}

					

@Inproceedings{CitationKey,
author = {Blau, Benjamin and Kr\"{a}mer, Jan and Conte, Tobias and van Dinther,
Clemens},
title = {{Service Value Networks}},
booktitle = {Proceedings of the 11th IEEE Conference on Commerce and Enterprise
Computing},
year = {2009},
address = {Vienna, Austria, 20-23 July 2009},
pages = {194-201},
editor = {Hofreiter, Birgit and Werthner, Hannes},
publisher = {IEEE},
note = {ISBN 978-0-7695-3755-9},
doi = {10.1109/CEC.2009.64},
abstract = {The current industry-driven trend in providing flexible software
services lays the ground for the new research area "service value networks"
(SVNs). We observe a rising number of industry-oriented publications provided
by research departments of large companies such as IBM or SAP as well as the
fact that more and more IS conferences offer special tracks on that issue.
However, when it comes to formalizing and economically analyzing such SVNs that
offer joint complex services to service customers, scientific approaches are
in their infancy. We intend to fill this research gap by providing a clear
understanding of service value networks by defining their characteristics, their
structure, and their components.

Mapping these aspects into a formalized model, we intend to establish a reference
point for future work in the area of service value networks.}}

					

@Inproceedings{CitationKey,
author = {Kr\"{a}mer, Jan},
title = {{Digital Convergence, Pricing Strategies and Firms' Profits in the
Telecommunication and Entertainment Media Industry}},
booktitle = {Proceedings of the 6th Conference on Telecommunication
Techno-Economics},
year = {2007},
address = {Helsinki, Finland, 14-15 June 2007},
pages = {1-8},
publisher = {IEEE},
note = {ISBN 978-1-4244-1233-4},
doi = {10.1109/CTTE.2007.4389896},
abstract = {Digital convergence of telecommunication and entertainment media
services drove former network monopolists into a prisoner's dilemma forcing
them to enter each others markets. In this reciprocal duopoly firms now offer
their services in a bundle, commonly known as triple play. I investigate whether
bundling is indeed a profitable pricing strategy for these services and if it
can facilitate market power leverage. I will show that bundle pricing serves
as a powerful leverage device for one firm in this industry. This is achieved
through a quality sorting effect accruing as the firms wish to shield themselves
from increased price competition in the market for bundles. Thereby, one firm
emerges as the high-quality, high-profit provider in both markets, whereas the
competing firm has to settle for low qualities and profits.}}

					

@Conference{CitationKey,
author = {Kr\"{a}mer, Jan and Wiewiorra, Lukas},
title = {{Net Neutrality and Fairness: An Empirical Investigation of Consumers'
Appreciation of Quality of Service in Internet Access}},
booktitle = {Workshop on Information Systems and Economics (WISE)},
year = {2012},
address = {Orlando, FL}}

					

@Conference{CitationKey,
author = {Astor, Philipp and Adam, Marc T. P. and Kr\"{a}mer, Jan},
title = {{Einfluss emotionaler Bilder auf das Bietverhalten}},
booktitle = {Tagung der Gesellschaft f\"{u}r experimentelle Wirtschaftsforschung},
year = {2011},
address = {N\"{u}rnberg, Germany}}

					

@Conference{CitationKey,
author = {Astor, Philipp J. and Adam, Marc T. P. and Kr\"{a}mer, Jan},
title = {{Emotion Induction in Auctions}},
booktitle = {Annual International Meeting of the Economic Science Association},
year = {2011},
address = {Chicago, USA}}

					

@Conference{CitationKey,
author = {Adam, Marc T. P. and Kr\"{a}mer, Jan and Weinhardt, Christof},
title = {{Excitement and Time Pressure in Dutch Auctions}},
booktitle = {International Economic Association 16th World Congress},
year = {2011},
address = {Tsinghua University, Beijing, China}}

					

@Conference{CitationKey,
author = {Adam, Marc T. P.; Caspary, C.; Kr\"{a}mer, J.},
title = {{Emotionen und Zeitdruck in der Japanischen Auktion}},
booktitle = {Tagung der Gesellschaft f\"{u}r experimentelle Wirtschaftsforschung},
year = {2010},
address = {Luxembourg, Luxembourg}}

					

@Conference{CitationKey,
author = {K\"{o}hler, Philip and Kr\"{a}mer, Jan and Anandasivam, Arun},
title = {{Cloud Computing: New Business Opportunities for Telecommunications
Companies?}},
booktitle = {2010 European Regional ITS Conference},
year = {2010},
address = {Copenhagen, Denmark},
organization = {International Telecommunications Society},
url = {http://www.econstor.eu/dspace/handle/10419/44316},
key = {Koehler2010c}}

					

@Conference{CitationKey,
author = {Adam, M. T. P. and Kr\"{a}mer, Jan and Weinhardt, Christof},
title = {{Towards Understanding Auction Fever}},
booktitle = {World Meeting of the Economic Science Association (ESA)},
year = {2010},
address = {Copenhagen, Denmark}}

					

@Conference{CitationKey,
author = {Elsner, Helmuth and Kr\"{a}mer, Jan},
title = {{Management komplexer Unternehmensportale – Herausforderungen und
L\"{o}sungsans\"{a}tze}},
booktitle = {72. Wissenschaftliche Jahrestagung des Verbandes der Hochschullehrer
f\"{u}r Betriebswirtschaft},
year = {2010},
address = {Bremen, Germany}}

					

@Conference{CitationKey,
author = {Kr\"{a}mer, Jan; Wiewiorra, Lukas},
title = {{Innovation through Discrimination!? - A Formal Analysis of the Net
Neutrality Debate}},
booktitle = {The 8th Annual International Industrial Organization Conference
(IIOC)},
year = {2010},
address = {Vancouver, Canada},
month = {May}}

					

@Conference{CitationKey,
author = {Elsner, Helmuth and Kr\"{a}mer, Jan},
title = {{Phasen und Herausforderungen bei der Entwicklung eines
Unternehmensportals}},
booktitle = {1. Konferenz zu Mitarbeiterportalen in der Unternehmenspraxis
(MiPo'10)},
year = {2010},
address = {Aalen, Germany},
abstract = {Zur Unterst\"{u}tzung von Finanzprozessen setzt die Finanzabteilung
der Bayer AG seit 2001 auf eine Portall\"{o}sung, die seitdem kontinuierlich
erweitert wurde. Heute  bietet das Portal heute \"{u}ber siebzig verschiedene
Dienste f\"{u}r mehr als 2000 Mitarbeiter weltweit an. Bei der Weiterentwicklung
des Portals wurden drei sich \"{u}berschneidende Phasen durchlaufen: Zun\"{a}chst
wurde das Portal an bestehende Software und Datenquellen angebunden und konnte
somit zuvor heterogene Systeme verkn\"{u}pfen. Anschlie\ssend wurden intelligente
Dienste entwickelt, die die so zusammengef\"{u}hrten Daten zur weiterf\"{u}hrenden
Analyse nutzen, um so wiederum neue Informationen bereitzustellen. Aktuell wird
in der dritten Phase die Einbindung von Wissensmanagement- und
Kollaborations-Diensten vorangetrieben, mit dem Ziel, das Portal als zentrales
Element der Finance-Community zu etablieren. Im Rahmen dieser Phasen wurden
zahlreiche Herausforderungen an das Management von Unternehmensportalen
identifiziert und L\"{o}sungsstrategien vorgeschlagen, die dazu beitragen
k\"{o}nnen, das Portal als zentrale Unternehmensanwendung zu etablieren und
gleichzeitig eine hohe Nutzerakzeptanz zu gew\"{a}hrleisten.}}

					

@Conference{CitationKey,
author = {Adam, M. T. P. and Kr\"{a}mer, Jan and Weinhardt, Christof},
title = {{A Theory of Bid Protraction: Evidence from a Physioeconomic
Experiment}},
booktitle = {Tagung der Gesellschaft f\"{u}r experimentelle Wirtschaftsforschung},
year = {2009},
address = {Essen, Germany},
abstract = {Several previous experimental studies have discovered that seller's
revenue in Dutch auctions depends on the speed at which the standing price is
decreased: Slow Dutch auctions generally yield higher seller’s revenues than
fast Dutch auctions. This effect is commonly explained by the fact that auction
participants experience a “utility of suspense”, which last longer in slow Dutch
auctions, such that bidder’s are willing to accept higher prices there. In a
physioeconomic experiment, we show to the contrary that fast Dutch auctions
are more exciting to bidders. Furthermore, we provide physiological evidence
for an alternative explanation of the observed price differentials in Dutch
auctions with different clock speeds: Although bidders have in principle similar
perceptions about the price at which they intend to stop the clock in both
treatments, they refrain from bidding 2-3 seconds longer before they actually
stop the clock. This grace period is invariant of the clock-speed! However,
in this amount of time the standing price has decreased more at faster clock
speeds, which accurately explains the difference in final prices.}}

					

@Conference{CitationKey,
author = {Adam, Marc T.P. and Kr\"{a}mer, Jan and Weinhardt, Christof},
title = {{The Impact of Clock Speeds on Bidders' Arousal in Dutch Auctions}},
booktitle = {3rd Nordic Conference on Behavioral and Experimental Economics},
year = {2008},
address = {Copenhagen, Denmark},
abstract = {Previous experimental studies suggest that seller's revenue in Dutch
auctions depends on the speed at which the standing price

is decreased. This eect is commonly explained by the fact that auction speed
has a direct eect on bidders' utility of suspense. We provide experimental
evidence that dierent clock speeds indeed have an impact on bidders' emotional
arousal, which in turn influences market behavior and outcome. To this extend
a bidder's skin conductance levels have been measured while participating in
Dutch auctions with varying clock speeds. The main nding of our physio-economic
study is that the degree of emotional arousal is signicantly higher in fast
Dutch auctions. Thereby we provide evidence for the missing link between the
utility of suspense theory and truly experienced competitive arousal.}}

					

@Conference{CitationKey,
author = {Kr\"{a}mer, Jan},
title = {{Bundling as a Leverage Device in Quality Differentiated Duopolies
with Home Markets}},
booktitle = {34th Conference of the European Association for Research in
Industrial Economics (EARIE)},
year = {2007},
address = {Valencia, Spain}}

					

@Article{CitationKey,
author = {Kr\"{a}mer, Jan},
title = {{Deutsche Telekom: Sind Fair-Use-Flatrates wirklich fair?}},
journal = {Wirtschaftsdienst},
year = {2013},
volume = {93},
pages = {282},
number = {5},
month = {May},
note = {Kommentar},
doi = {10.1007/s10273-013-1524-2},
url = {http://www.wirtschaftsdienst.eu/downloads/getfile.php?id=2977}}

					

@Article{CitationKey,
author = {Kr\"{a}mer, Jan and Wiewiorra, Lukas and Weinhardt, Christof},
title = {{Net Neutrality in the United States and Europe}},
journal = {CPI Antitrust Chronicle},
year = {2012},
volume = {3},
pages = {Article 3},
number = {2},
month = {March},
url =
{https://www.competitionpolicyinternational.com/net-neutrality-in-the-united-states-and-europe/}}

					

@Misc{CitationKey,
author = {Adam, M. T. P.; Kr\"{a}mer, Jan; Weinhardt, Christof; Ehrhart,
Karl-Martin},
title = {{Investigating Auction Fever}},
howpublished = {in: Dreier, T.; Kr\"{a}mer, J.; Studer, R.; Weinhardt, C. (eds.),
Information Management and Market Engineering: Vol. II Studies on eOrganisation
and Market Engineering. Karlsruhe: KIT Scientific Publishing. 141–157},
year = {2010},
note = {ISBN: 978-3-86644-589-5}}

					

@Misc{CitationKey,
author = {Wiewiorra, Lukas and Kr\"{a}mer, Jan and Weinhardt, Christof and
Ehrhart, Karl-Martin},
title = {{Consumer Perception of Time Based Pricing}},
howpublished = {in: Dreier, T.; Kr\"{a}mer, J.; Studer, R.; Weinhardt, C. (eds.),
Information Management and Market Engineering: Vol. II. Studies on eOrganisation
and Market Engineering. Karlsruhe: KIT Scientific Publishing. 179—190. ISBN:
978-3-86644-589-5},
year = {2010}}

					

@Misc{CitationKey,
author = {Kr\"{a}mer, Jan and Berninghaus, Siegfried and Weinhardt, Christof},
title = {{Competing on Many Fronts: Entry Networks in an Economy of Multi-Product
Firms}},
howpublished = {in: Dreier, T.; Studer, R.; Weinhardt, C. (eds.), Information
Management and Market Engineering. Universit\"{a}tsverlag Karlsruhe. 139–151},
year = {2006},
url =
{http://www.amazon.de/Information-Management-Market-Engineering-Thomas/dp/3866440596/}}

					

@Unpublished{CitationKey,
author = {Kr\"{a}mer, Jan and Wiewiorra, Lukas},
title = {{Net neutraliy and fairness: An empirical investigation of consumers'
appreciation of quality of service in Internet access}},
note = {Presented at: European Conference of the International Telecommunications
Society (ITS), Vienna, 2012; Telecommunications Policy Research Conference (TPRC),
Arlington, VA, 2012; Workshop on Information Systems and Economics, Orlando,
FL, 2012},
year = {2013},
url = {http://ssrn.com/abstract=2031034},
abstract = {The academic debate on net neutrality has thus far focused on the
relationship between Internet service providers (ISPs) and content providers.
In this paper instead, we investigate the drivers for Internet users' appreciation
of a differentiated services regime in lieu of net neutrality. User tiering,
i.e., a pay-for-priority arrangement between the ISP and an end user, is usually
not scrutinized by policy makers. Nevertheless, user tiering is not yet offered
by ISPs. We conjecture that the individual perception of fairness is important
for an user's appreciation of user tiering and, therefore, also for the success
of quality of service (QoS) offerings in next generation networks. We
conceptualize different notions of fairness and show in a representative survey
among German Internet users that the perception of fairness is decisive for
the attitude towards user tiering as well as for the willingness-to-pay for
tiered Internet access. Moreover, we compare user tiering that is provided via
a relative QoS mechanism (in which prioritized transmissions are expedited over
concurrent non-prioritized transmissions) to a dedicated QoS mechanism (in which
a portion of the available transmission capacity is reserved explicitly for
the priority service) in this regard and find remarkable differences. In general,
users prefer a neutral Internet access over a tiered access and a dedicated
over a relative QoS mechanism. However, given our data, it is doubtful whether
ISPs are able to profit from a departure of net neutrality in Internet access
after all. We find that the introduction of user tiering will likely render
customers upset and will erode the willingness-to-pay for the non-prioritized
best-effort class.}}

					

@Unpublished{CitationKey,
author = {Kr\"{a}mer, Jan and Vogelsang, Ingo},
title = {{Co-Investments and Tacit Collusion in Regulated Network Industries:
Experimental Evidence}},
note = {Working Paper. Presented at the European Conference of the International
Telecommunications Society (ITS), Vienna, 2012; Conference of the European
Association of Research in Industrial Economics (EARIE), Rome, 2012},
month = {July},
year = {2012},
url = {http://ssrn.com/abstract=2119927},
key = {kraemervogelsang2012},
abstract = {With the use of a laboratory experiment, we show the effects of
co-investments on coverage, competition and price collusion in regulated network
industries. On the one hand, co-investments turn out not to be a significant
driver of new infrastructure investments beyond the level achieved by access
regulation and they seem to facilitate tacit price collusion. On the other hand,
co-investments economize on infrastructure investment costs and necessitate
communication, which partially offset the aforementioned effects. In fact,
communication between the firms on their future coverage, especially outside
co-investments, seems to have a positive effect on investments. However, the
surprising message of the experiment is that tacit collusion happens under
co-investment although there is no reason to believe that it should and although
we made almost every effort to prevent it. Our results indicate that regulators
should evaluate co-investments with scrutiny as there are definite drawbacks
that must be considered.}}

					

@Unpublished{CitationKey,
author = {Kr\"{a}mer, Anne and Kr\"{a}mer, Jan},
title = {{Flexibility of Delivery Frequency in Logistics Competition}},
note = {Working Paper, Karlsruhe Institute of Technology},
month = {March},
year = {2010},
url = {http://ssrn.com/abstract=1583015},
abstract = {We investigate the strategic impact of flexible delivery frequencies
on the competition of logistics service providers (LSPs) in a supply chain.
LSPs compete for customers who choose an exclusive service provider based on
their individual preference, prices and inventory costs. The service provider
which offers the higher delivery frequency is more attractive to customers,
because inventory holding costs are kept low. In reverse, higher delivery
frequencies entail higher transportation costs for the LSPs (frequency effect),
which is only partially offset by a community cost effect that captures the
economies of scale from larger market share and synergies from increased load
efficiency. We consider a scenario in which only one of the two LSPs can choose
its delivery frequency strategically. Our main result is that flexibility in
frequency choice is only a strategic advantage for the LSP if customers' inventory
holding costs are relatively high compared to transportation costs. In this
case customers especially appreciate the high delivery frequencies and the
flexible LSP is able to satisfy this demand. However, when inventory holding
costs are comparably small with respect to the LSPs' transportation costs, the
inflexible LSP is at an advantage. In this case, inflexibility acts as a credible
strategic commitment which the flexible LSP can only react to. Furthermore,
low inventory holding costs lead to a situation in which the LSP with the flexible
delivery frequency faces the dilemma whether to choose its optimal delivery
frequency and to make less profit than his competitor or to forfeit some of
its own profits in order to make larger profits than the other LSP.}}

					

@Unpublished{CitationKey,
author = {Kr\"{a}mer, Jan and Conte, Tobias and Blau, Benjamin and van Dinther,
Clemens and Weinhardt, Christof},
title = {{Service Value Networks: Unleashing the Combinatorial Power of Service
Mashups}},
note = {Working Paper, Karlsruhe Institute of Technology},
year = {2010},
url = {http://ssrn.com/abstract=1582902},
abstract = {The long tail phenomenon has been heavily discussed in recent years.
What has been neglected so far is its striking relevance for electronic services.
Whereas consumers’ expectations about information goods are often vague and
transient, their requirements are pronounced and specific when it comes to the
functional and non-functional characteristics of electronic services. Moreover,
modular services can be combined and configured into service mashups that meet
virtually every conceivable consumer requirement. In this vein, the long tail
phenomenon can be leveraged into a new dimension -- the long valley, where every
service exerts positive network externalities on the remaining services, thereby
spurring an increase in supply and demand. The combinatorics of constructible
service mashups are enabled by universally accessible service orchestration
platforms known as Service Value Networks (SVNs). This article shall not only
pave the way for a rising research area on a new business trend, but will also
help business actors to harness the opportunities opened up by SVNs.}}