Heidelberg, Germany
Heidelberg, Germany
Time filter
Source Type

Bhattacharjee S.,HIT | Roy S.,HIT | Ghosh S.,University of Iowa | Dasbit S.,IIEST
ACM International Conference Proceeding Series | Year: 2017

Opportunistic or Delay-tolerant networks (DTNs) may be used as a viable option for exchanging situational information during post-disaster communication in the absence of existing communication infrastructure. As opposed to traditional communication networks, situational information dissemination in DTNs depends on the degree of intermittent connectivity among the mobile nodes. Higher degree of connectivity implies smaller delay to disseminate situational information which results in better knowledge sharing. The degree of intermittent connectivity is influenced by mobility pattern of the nodes which is heterogeneous in nature. In this work, we attempt to formulate an empirical relationship between the degree of intermittent connectivity and extent of situational knowledge dissemination over DTNs in order to quantify the impact of the node mobility on the inter-shelter knowledge transfer. In the absence of prior knowledge about the mobility patterns, we consider only the broad features of the impact. We introduce two metrics, Total Encounters and Knowledge Sharing Ratio. Total Encounters depends on node density, average movement speed of the nodes and elapsed time after initial node deployment. It serves as an indicator for estimating the degree of intermittent connectivity. The extent of situational information dissemination over an entire network is measured in terms of Knowledge Sharing Ratio. The relationship between Total Encounters and Knowledge Sharing Ratio is validated using the real mobility traces of volunteers captured from a field trial carried out in a disaster affected area. This analysis also helps us to formulate a suitable strategy for deployment of volunteer nodes in a post-disaster scenario. © 2017 ACM.

Peters A.,HIT | Haberer T.,HIT | Scheeler U.,Massachusetts Institute of Technology
IPAC 2016 - Proceedings of the 7th International Particle Accelerator Conference | Year: 2016

When the University Hospital Heidelberg took over the responsibility for the Marburg Ion-Beam Therapy Centre (MIT), HIT as their daughter company was mandated to build up the operation team, especially for the accelerator. Based on long-standing experiences of HIT a very similar personnel concept was already available to be adapted to the MIT specialties. Within 9 months the directly started hiring process resulted in three technical teams with excellent engineers and technicians but with little or no accelerator experience. In parallel, three accelerator physicists were appointed for the executive team of MIT. Nevertheless for all hired persons a training program was set up consisting of technical instructions, lectures on fundamental accelerator physics and control system basics. These common trainings were complemented by individual skills development schedules for the tasks in the technical teams. HIT accelerator experts substantially carried out the recommissioning but in addition the new MIT employees were trained in designated shifts in the control room. Thus after only 13 months the MIT operation crew was able to operate the accelerator facility from the first patient treatment day on. Copyright © 2016 CC-BY-3.0 and by the respective authors.

He Z.,Harbin Institute of Technology | He Z.,Sun Yat Sen University | Li J.,HIT
Expert Systems with Applications | Year: 2014

Kernel-based learning strategies have recently emerged as powerful tools for hyperspectral classification. However, designing optimal kernels is still a challenging issue that needs to be further investigated. In this paper, we propose a multiple data-dependent kernel (MDK) for classification of HSI. Core ideas of the MDK are twofold: (1) optimizing the combination of multiple basic kernels in merit of centered kernel alignment (CKA), which can evaluate the degree of agreement between a kernel and a learning task; (2) optimizing the coefficients of data-dependent kernel (DK) by virtue of Fisher's discriminant analysis (FDA), which can measure the between-class and within-class separability of the data simultaneously. Furthermore, we apply the proposed MDK to two state-of-the-art classifiers, i.e. support vector machine (SVM) and sparse representation classifier (SRC). Experimental results conducted on three benchmark HSIs with different spectral and spatial resolutions validate the feasibility of the proposed methods. © 2014 Elsevier Ltd. All rights reserved.

Pal A.K.,HIT | Mudi R.K.,Jadavpur University
Communications in Computer and Information Science | Year: 2011

A robust and simple self-tuning fuzzy PI controller (STFPIC) for high-order as well as non-linear dead-time processes is proposed. The output scaling factor (SF) of the STFPIC is updated by a fuzzy gain modifier (β), which is parameterized by the process ultimate gain (K u) and ultimate period (P u) obtained through relay feedback approach. Effectiveness of the propose STFPIC is demonstrated in terms of several performance indices. © 2011 Springer-Verlag.

Sarkar S.,Jadavpur University | Sekh M.,H.I.T. | Mitra S.,Jadavpur University | Bhattacharyya B.,Jadavpur University
Precision Engineering | Year: 2011

Wire bending due to gap force is a major cause of imprecision in WEDM applications. To achieve higher precision and accuracy the knowledge of gap force and wire lag is extremely essential. In the present research, an in depth study on wire lag phenomenon has been carried out. A novel method to measure gap force intensity and wire lag under any given machining condition has been proposed by developing an analytical model. Experiments were carried out to verify the proposed model. Beside this, the impact of wire deflection on profile accuracy during cutting cylindrical job has been investigated. Based upon the developed analytical model an effective method has been proposed to eliminate this inaccuracy using wire lag compensation technique. The research finding will lead to better understanding of the gap force phenomena and will promote significant development in the domain of high precision WEDM. © 2011 Elsevier Inc. All rights reserved.

Pal A.K.,HIT | Mudi R.K.,Jadavpur University | De Maity R.R.,DBCREC
Advances in Intelligent Systems and Computing | Year: 2013

A non-fuzzy self-tuning scheme is proposed for Fuzzy PD controller in this paper. To eliminate the design complexity, output scaling factor (SF) of the proposed fuzzy controller is updated according to the process trend by a gain modification factor, which is determined by the normalized change of error of the system and its number of fuzzy partitions. The proposed non-fuzzy self-tuning fuzzy PD controller (NFST-FPDC) is demonstrated on a laboratory scale overhead crane. Moving a suspended load along a pre-specified path is not an easy task when strict specifications on the swing angle and transfer time need to be satisfied. In this study, twin NFST-FPDC are designed to control the trolley position of the crane and swing angle of the load. The proposed non-fuzzy gain tuning scheme guarantees a fast and precise load transfer and the swing suppression during load movement, despite of model uncertainties. © 2013 Springer-Verlag.

Chunjiao X.,HIT | Dianhui C.,HIT | Chunshan L.,HIT
Proceedings of International Conference on Service Science, ICSS | Year: 2016

Since IBM proposed the concept of 'Smarter Planet', the construction of 'Smarter City' has been spread all over the world. Our country's construction in 'Smarter City' is just at the beginning, and it appears with serious information silos, although data has been simply integrated, there still exists the problem of single source of data, fixed monitoring position and details can be hardly found. In response to these problems, this paper presents the design of City Event Management System, which integrates the data from public monitoring facilities, social media and crowd sourcing. Meanwhile, topic model has been used to extract city events, these events can be classified in different categories by matching with the predefined repository. The proposed system pushes events as well as relative viable solutions to users. Hence, problems of the fixed monitoring positions are solved via users' activity, and their high sensitivity of city events. Issues on single source of data are solved by the data integration of social media and crowd sourcing. Challenges of information silos are overcame by strength the data mobility. © 2015 IEEE.

Yu R.L.,HIT | Jin J.,HIT
Advanced Materials Research | Year: 2014

To achieve high-precision tracking control of motor speed for magnetically suspended reaction wheel, mathematical model combining BUCK converter with permanent magnet brushless DC motor system is established, and a MSRFW speed mode Passivity-based control method is presented. A passivity-based controller of speed tracking is designed in order to enhance the speed of tracking performance. Experiments on MSRW platform show that passivity-based control method can improve the speed of the dynamic response and tracking accuracy, from which the validity is verified. © (2014) Trans Tech Publications, Switzerland.

Pal A.K.,HIT | Chakrabarty J.,HIT
Advances in Intelligent Systems and Computing | Year: 2015

In this paper, a new non-fuzzy self-adaptive scheme is proposed for optimal swing up control of the inverted pendulum system. Further, the system stabilization is compared against an automatic fuzzy-based self-tuning technique. Our work proposes a twin fuzzy control scheme for effective control of cart position and inverted pendulum angle. A comparative analysis through simulation demonstrates the feasibility and reliability of the proposed approach. © Springer India 2015.

Das S.K.,HIT | Syam P.,HIT
Lecture Notes in Electrical Engineering | Year: 2015

Matrix converter is an alternative topology for a solid state frequency changer without any reactive elements like inductors and capacitors. One of the major obstacles of this topology is the complex commutation of the bi directional switches in absence of natural free wheeling path for the inductive currents. A detailed study has been made here to understand the limitations and possible improvement of the existing current commutation techniques in this paper. A universal and synchronous commutation scheme for all the IGBTs is devised so that commutation can smoothly take place as and when required within the minimum possible time depending on the switching time of the IGBT used. The different aspects of this commutation are verified through MATLB simulink. Possibility of step less current commutation is explored. © Springer India 2015.

Loading HIT collaborators
Loading HIT collaborators