59 research outputs found
A Generalized Flow Network for Freight Car Dispatching
In the freight car dispatching problem empty freight cars have to be assigned to known demands respecting a given time horizon and certain constraints. The goal is to minimize the resulting transportation costs. One of the constraints is that customers can specify the type of cars they want. It is possible, however, that cars of certain types can be substituted by other cars either in a 1-to-1 fashion or at different exchange rates. We show that these substitutions make the dispatching problem NP-complete. We model the dispatching problem as a generalized integral minimum cost flow problem on a specific directed graph. We show that in our setting its linear relaxation is half-integral. Using rounding techniques, the LP-relaxation can be transformed to a dispatching with small constraint violation at the same cost, or, under additional assumptions, to a 4 -approximation. In practice, both ideas are combined to a heuristic approach without further assumptions. We conclude with computational results for this heuristic on application data provided by DB Schenker Rail Deutschland AG in context of a joint R-and-D project together with the Technical University of Kaiserslautern
Integer Flows with Multipliers 1 and 2
The problem to find a valid Integer generalized flow is long known to be NP-complete (S. Sahni, 1974). We show that the problem is still hard restricted to multipliers 1 and 2 and that optimal solutions with (almost) arbitrary fractions can occur. In some (still NP-hard) application motivated network instances optimal solutions are halfintegral. To solve the latter (optimally) we modify the Successive Shortest Path Algorithm and try to (heuristically) find acceptable integral solutions
Erich Fromm and the Critical Theory of Communication
Erich Fromm (1900-1980) was a Marxist psychoanalyst, philosopher and socialist humanist. This paper asks: How can Fromm’s critical theory of communication be used and updated to provide a critical perspective in the age of digital and communicative capitalism?
In order to provide an answer, the article discusses elements from Fromm’s work that allow us to better understand the human communication process. The focus is on communication (section 2), ideology (section 3), and technology (section 4). Fromm’s approach can inform a critical theory of communication in multiple respects: His notion of the social character allows to underpin such a theory with foundations from critical psychology. Fromm’s distinction between the authoritarian and the humanistic character can be used for discerning among authoritarian and humanistic communication. Fromm’s work can also inform ideology critique: The ideology of having shapes life, thought, language and social action in capitalism. In capitalism, technology (including computing) is fetishized and the logic of quantification shapes social relations. Fromm’s quest for humanist technology and participatory computing can inform contemporary debates about digital capitalism and its alternatives
The immune system as a foundation for immunologic therapy and hematologic malignancies: a historical perspective.
In this review we aim to provide a historical overview of the immunotherapeutic approaches which have been developed for the treatment of hematological malignancies. After briefly summarizing the development of the theory of cancer immune surveillance, we describe how initial studies discovering the efficacy of the immune-mediated graft-versus-tumor effects after allogeneic hematopoietic cell transplantation led to new transplantation approaches (termed non-myeloablative transplantation) relying almost exclusively on graft-versus-tumor effects for tumor eradication. We then summarize important steps in the development of tumor vaccines and autologous adoptive immunotherapy in patients with hematological malignancies. Finally, we describe historical discoveries leading to the recent success with monoclonal antibodies as treatment for lymphomas, chronic lymphocytic leukemia, and acute myeloid leukemia
Characterization of highly frequent epitope-specific CD45RA(+)/CCR7(+/- )T lymphocyte responses against p53-binding domains of the human polyomavirus BK large tumor antigen in HLA-A*0201+ BKV-seropositive donors
Human polyomavirus BK (BKV) has been implicated in oncogenic transformation. Its ability to replicate is determined by the binding of its large tumor antigen (LTag) to products of tumor-suppressor genes regulating cell cycle, as specifically p53. We investigated CD8+ T immune responses to BKV LTag portions involved in p53 binding in HLA-A*0201+ BKV LTag experienced individuals. Peptides selected from either p53-binding region (LTag(351–450 )and LTag(533–626)) by current algorithms and capacity to bind HLA-A*0201 molecule were used to stimulate CD8+ T responses, as assessed by IFN-γ gene expression ex vivo and detected by cytotoxicity assays following in vitro culture. We observed epitope-specific immune responses in all HLA-A*0201+ BKV LTag experienced individuals tested. At least one epitope, LTag(579–587); LLLIWFRPV, was naturally processed in non professional antigen presenting cells and induced cytotoxic responses with CTL precursor frequencies in the order of 1/20'000. Antigen specific CD8+ T cells were only detectable in the CD45RA+ subset, in both CCR7+ and CCR7- subpopulations. These data indicate that widespread cellular immune responses against epitopes within BKV LTag-p53 binding regions exist and question their roles in immunosurveillance against tumors possibly associated with BKV infection
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Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks
无线传感器网络,作为全球未来十大技术之一,集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术,可实时感知、采集、处理、传输网络分布区域内的各种信息数据,在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议,并针对大规模的无线传感器网络设计了一种树状路由协议,它根据节点地址信息来形成路由,从而简化了复杂繁冗的路由表查找和维护,节省了不必要的开销,提高了路由效率,实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR(AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位:工学硕士院系专业:信息科学与技术学院通信工程系_通信与信息系统学号:2332007115216
All-sky search for long-duration gravitational wave transients with initial LIGO
We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10–500 s in a frequency band of 40–1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10[superscript -5] and 9.4×10[superscript -4] Mpc[superscript -3] yr[superscript -1] at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves.Carnegie TrustDavid & Lucile Packard FoundationAlfred P. Sloan FoundationNational Science Foundation (U.S.
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