ppxscal/embedding_network huggingface dataset:
Label fusion using performance estimation with iterative label selection
Authors: T. R. Langerak, U. A. Van Der Heide, I. M. Lips, A. N. T. J. Kotte, M. Van Vulpen, J. P. W. Pluim
Venue: Proceedings of the Sixth IEEE international conference on Symposium on Biomedical Imaging: From Nano to Macro (2009)

Atlas-based segmentation is a well-known method of automatically computing a segmentation. When multiple atlases are available, then each atlas can be used to compute a 'label', which is an estimation of the ground truth segmentation of a target image. By combining these labels, a more accurate approximation of the ground truth segmentation can be made. A common method to combine labels is the STAPLE algorithm, but this method fails when the performance of the labels highly varies. Other methods select labels based on their estimated performance, but combine them using a simple majority vote procedure. In this paper, a simpler variant of the STAPLE algorithm is presented that iteratively selects labels. Results are given that show that the proposed method outperforms STAPLE in an application to segmentation of the prostate.
High-rate, 2-group ML-decodable STBCs for 2m transmit antennas
Authors: K. Pavan Srinath, B. Sundar Rajan
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

A Space-Time Block Code (STBC) in K--variables is said to be g-Group ML-Decodable (GMLD) if its Maximum-Likelihood (ML) decoding metric can be written as a sum of g independent terms, with each term being a function of a subset of the K variables. In this paper, a construction method to obtain high-rate, 2-GMLD STBCs for 2m transmit antennas, m > 1, is presented. The rate of the STBC obtained for 2m transmit antennas is 2m-2+1/2m complex symbols per channel use. The design method is illustrated for the case of 4 and 8 transmit antennas. The code obtained for 4 transmit antennas is equivalent to the rate-5/4 Quasi-Orthogonal design (QOD) proposed by Yuen, Guan and Tjung.
Entropy of the induced transformations associated with the interval algorithm
Authors: Hiroshi Fujisaki
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

We have introduced the induced transformations associated with the interval algorithm. In view of the entropy of the induced transformations, the stopping time of the algorithm is evaluated. Sharp upper and lower bounds of the mean value of the stopping time are given for the case that the source and the target have uniform distributions.
Simple balanced codes that approach capacity
Authors: Kees A. Schouhamer Immink, los H. Weber
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

The prior art construction of sets of balanced codewords by Knuth is attractive for its simplicity and absence of look-up tables, but the redundancy of the balanced codes generated by Knuth's algorithm falls a factor of two short with respect to capacity. We present a new construction, which is simple, does not use look-up tables, and is less redundant than Knuth's construction. In the new construction, the user word is modified in the same way as in Knuth's construction, that is by inverting a segment of user symbols. The prefix that indicates which segment has been inverted, however, is encoded and decoded in a different, more efficient, way.
Development and quantitative analysis of an adaptive scheme for Bluetooth and Wi-Fi co-existence
Authors: Tanim M. Taher, Kunal Rele, Dennis Roberson
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

A smart radio algorithm to supplement the Adaptive Frequency Hopping (AFH) scheme used by Bluetooth devices is developed and studied. The investigation focuses on the Media Access Control (MAC) layer of the Bluetooth. Collision detection, and Bluetooth channel hopping information are used to detect when an IEEE 802.11 wireless Access Point (AP) is operating and the AP's Radio Frequency (RF) channel number (1 through 11). The algorithm then adapts the Bluetooth device to avoid the spectral region occupied by the AP. The performance of this scheme is tested via simulation, and compared with the native AFH system employed by Bluetooth devices.
Sum capacity of multi-source linear finite-field relay networks with fading
Authors: Sang-Woon Jean, Sae-Young Chung
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

We study a fading linear finite-field relay network having multiple source-destination pairs. Because of the interference created by different unicast sessions, the problem of finding its capacity region is in general difficult. We observe that, since channels are time-varying, relays can deliver their received signals by waiting for appropriate channel realizations such that the destinations can decode their messages without interference. We propose a block Markov encoding and relaying scheme that exploits such channel variations. By deriving a general cut-set upper bound and an achievable rate region, we characterize the sum capacity for some classes of channel distributions and network topologies. For example, when the channels are uniformly distributed, the sum capacity is given by the minimum average rank of the channel matrices constructed by all cuts that separate the entire sources and destinations. We also describe other cases where the capacity is characterized.
Secure diversity-multiplexing tradeoffs in MIMO relay channels
Authors: Kiran T. Gowda, Tony Q. S. Quek, Hyundong Shin
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 2 (2009)

Wireless networks are susceptible to eavesdropping due to the inherent broadcast nature of the wireless medium. However, it is also this broadcast nature of wireless communications that allows cooperation among multiple users or relay nodes. Thus, it is unclear how cooperation and secrecy interacts, particularly in the scenario when each node in the network is equipped with multiple antennas (MIMO). In this paper, we consider the information theoretic secure transmission in a classical four node wiretap relay network, consisting of a source node, a destination node, and a relay node, in the presence of a fourth adversarial wiretapper node that can observe all transmissions from the source as well as the relay node. For a MIMO quasi-static fading channel model between every pair of nodes, we explore the importance of degrees of freedom in providing secure transmissions, through secrecy outage analysis in the high signal-to-noise ratio regime. We characterize the achievable diversity versus secure multiplexing gain tradeoff for decode-and-forward as well as compress-and-forward relaying, under the full-duplex constraint.
Coded modulation with a constraint on the minimum channel symbol duration
Authors: Anil Mengi, A. J. Han Vinck
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

A coded modulation scheme is described which improves the error performance of constant envelope data transmission without requiring more bandwidth. This is achieved by controlling the minimum channel symbol duration by run-length limited (RLL) encoding. It is shown that the same amount of information can be transmitted within the same minimum channel symbol duration with a coding gain of 4 dB compared with the uncoded modulation. The bandwidth is analyzed using the power spectra of channel signals. As a practical application, we consider bandwidth limited transmission with a restriction on the maximum transmitted power. Following a discussion of a coded modulation principle, constructed RLL codes and the evaluation of their code performances are provided, and the simulation results for BPSK and 2-FSK modulations are presented. Comparisons are strictly made on the basis of equal information rate and the same minimum channel symbol duration.
A scalable decision tree system and its application in pattern recognition and intrusion detection
Authors: Xiao-Bai Li
Venue: Decision Support Systems (2005)

One of the most challenging problems in data mining is to develop scalable algorithms capable of mining massive data sets whose sizes exceed the capacity of a computer's memory. In this paper, we propose a new decision tree algorithm, named SURPASS (for Scaling Up Recursive Partitioning with Sufficient Statistics), that is highly effective in handling such large data. SURPASS incorporates linear discriminants into decision trees' recursive partitioning process. In SURPASS, the information required to build a decision tree is summarized into a set of sufficient statistics, which can be gathered incrementally from the data, by reading a subset of the data from storage space to main memory one at a time. As a result, the data size that can be handled by this algorithm is independent of memory size. We apply SURPASS to three large data sets pertaining to pattern recognition and intrusion detection problems. The results indicate that SURPASS scales up well against large data sets and produces decision tree models with very high quality.
Enhanced group-based key management scheme for wireless sensor networks using deployment knowledge
Authors: Ngo Trong Canh, P. T. H. Truc, Tran Hoang Hai, Le Xuan Hung, Young-Koo Lee, Sungyoung Lee
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

Key establishment plays a central role in authentication and encryption in wireless sensor networks, especially when they are mainly deployed in hostile environments. Because of the strict constraints in power, processing and storage, designing an efficient key establishment protocol is not a trivial task. Compared with public key cryptography, symmetric key cryptographic with key predistribution mechanism is more suitable for large-scale wireless sensor networks. Most of previous solutions have some issues on performance and security capabilities. In this paper, we propose a novel key predistribution model using pre-deployment knowledge and random values in pairwise key generation to take advantage in terms of network connectivity, memory cost, energy for transmission and strong resilience against node capture attacks.
Agent-intermediated electronic markets in international freight transportation
Authors: Barrie R. Nault, Albert S. Dexter
Venue: Decision Support Systems (2006)

In many industries, agent-intermediated markets are inefficient because information about latent demand and supply never gets to market. We demonstrate how information technology (IT) in the form of an agent-intermediated electronic market (EM) alleviates this problem by enhancing the agent-as-market-maker using the international freight transportation industry as an example. We find that an EM increases agent participation and investment thereby increasing demand and supply. Because of tradeoffs between incentives for investment, the EM chooses a profit allocation between agents resulting in limited agent participation. In addition, when price depends on demand and supply balances, price and volume in the market can increase simultaneously.
Fixed gantry tomosynthesis system for radiation therapy image guidance based on a multiple source X-ray tube with carbon nanotube cathodes
Authors: Jonathan S. Maltz, Jens Fuerst, Ajay Paidi, Franz Fadler, Ali R. Bani-Hashemi, Frank Sprenger
Venue: Proceedings of the Sixth IEEE international conference on Symposium on Biomedical Imaging: From Nano to Macro (2009)

We present the design and simulation of a multiple source x-ray tube based on carbon nanotube cold cathode technology. The primary intended application is tomosynthesis-based 3D image guidance during external beam radiation therapy. The tube, which is attached to the gantry of a medical linear accelerator (linac) immediately below the multileaf collimator, operates within the voltage range of 80-160 kVp and contains a total of 52 sources that are arranged in a rectilinear array. This configuration allows for the acquisition of tomographic projections from multiple angles without any need to rotate the linac gantry. The x-ray images are captured by a standard amorphous silicon flat panel portal imaging device. The field-of-view (FOV) of the system corresponds to that part of the volume that is sampled by rays from all sources. The present tube and detector configuration provides an 8 cm×8 cm FOV in the plane of the linac isocenter when the 40.96 cm×40.96 cm imaging detector is placed 40 cm from the isocenter. Since this tomosynthesis application utilizes the extremities of the detector to record image detail relating to structures near the isocenter, simultaneous treatment and imaging is possible for most clinical cases, where the treated target is a small region close to the linac isocenter. The tomosynthesis images are reconstructed using the simultaneous iterative reconstruction technique (SART), which is accelerated using a graphics processing unit (GPU). We present details of the system design as well as simulated performance of the imaging system based on reprojections of patient CT images.
Comments on "broadcast channels with arbitrarily correlated sources"
Authors: Gerhard Kramer, Chandra Nair
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4 (2009)

The Marton-Gelfand-Pinsker inner bound on the capacity region of broadcast channels was extended by Han-Costa to include arbitrarily correlated sources where the capacity region is replaced by an admissible source region. The main arguments of Han-Costa are correct but unfortunately the authors overlooked an inequality in their derivation. The corrected region is presented and the absence of the omitted inequality is shown to sometimes admit sources that are not admissible.
TSA: time series adaptation for enhanced cell reselection in UMTS
Authors: Sanghun Pyo, SungHoon Seo, JooSeok Song
Venue: Proceedings of the 16th international conference on Telecommunications (2009)

Mobile Stations (MSs) operate in either idle mode or connected mode. However, previous studies have mainly focused on the connected mode even though the MSs remain their most of time in the idle mode. In this paper, we propose an efficient Cell Reselection algorithm, namely TSA (Time Series Adaptation), to decide the best cell in UMTS (Universal Mobile Telecommunication Systems). The proposed algorithm has the advantage of selecting the strongest RSCP cell out of neighboring cells for the cell reselection by utilizing time series parameters (e.g., β0 and β1). We evaluate the proposed cell reselection with TSA through the real-system testbed (Stand Alone Simulator). As a result, the TSA provides a proper decision for the cell reselection thereby avoiding the occurrence of unnecessary ping-pong cell reselection.
Lightweight fault-tolerance mechanism for distributed mobile agent-based monitoring
Authors: Jinho Ahn
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

Thanks to asynchronous and dynamic natures of mobile agents, a certain number of mobile agent-based monitoring mechanisms have actively been developed to monitor large scale and dynamic distributed networked systems adaptively and efficiently. Among them, some mechanisms attempt to adapt to dynamic changes in various aspects such as network traffic patterns, resource addition and deletion, network topology and so on. However, failures of some domain managers are very critical to providing correct, real-time and efficient monitoring functionality in a large-scale mobile agent-based distributed monitoring system. In this paper, we present a novel fault-tolerance mechanism to have the following advantageous features appropriate for large-scale and dynamic hierarchical mobile agent-based monitoring organizations. It supports fast failure detection functionality with low failure-free overhead by each domain manager transmitting heart-beat messages to its immediate higher-level manager. Also, it minimizes the number of non-faulty monitoring managers affected by failures of domain managers. Moreover, it allows consistent failure detection actions to be performed continuously in case of agent creation, migration and termination, and is able to execute consistent takeover actions even in concurrent failures of domain managers.
The mirror method of assessing segmentation quality in atlas label propagation
Authors: R. A. Heckemann, A. Hammers, P. Aljabar, D. Rueckert, J. V. Hajnal
Venue: Proceedings of the Sixth IEEE international conference on Symposium on Biomedical Imaging: From Nano to Macro (2009)

Atlas-based brain image segmentation quality is difficult to assess in the absence of reference target segmentations. We propose a measure of segmentation success based on transforming the atlas label twice: once by registering the atlas to the target and a second time by registering the target to the atlas. Each registration represents transformations by free-form deformations. The overlap between the twice-transformed label and the original ('mirror overlap') correlates with the forward overlap (between the once-transformed label and a target reference), especially for subcortical structures. Using mirror overlap as an atlas selection criterion results in improved segmentations versus random selection.
Relative entropy and score function: new information-estimation relationships through arbitrary additive perturbation
Authors: Dongning Guo
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 2 (2009)

This paper establishes new information-estimation relationships pertaining to models with additive noise of arbitrary distribution. In particular, we study the change in the relative entropy between two probability measures when both of them are perturbed by a small amount of the same additive noise. It is shown that the rate of the change with respect to the energy of the perturbation can be expressed in terms of the mean squared difference of the score functions of the two distributions, and, rather surprisingly, is unrelated to the distribution of the perturbation otherwise. The result holds true for the classical relative entropy (or Kullback-Leibler distance), as well as two of its generalizations: Rényi's relative entropy and the f-divergence. The result generalizes a recent relationship between the relative entropy and mean squared errors pertaining to Gaussian noise models, which in turn supersedes many previous information-estimation relationships. A generalization of the de Bruijn identity to non-Gaussian models can also be regarded as consequence of this new result.
CABAC based bit estimation for fast H.264 RD optimization decision
Authors: Li Liu, Xinhua Zhuang
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

Rate distortion (RD) optimization, which is used to decide the best coding mode of a macroblock (MB) in H.264/AVC video coding standard, is a very efficient technique to improve coding performance. On the other hand, this RD optimization process also incurs a considerable complexity increase of the encoder. To reduce computational cost of RD optimization, fast bit estimation method can be adopted to avoid entropy coding computation during the mode decision process of H.264/AVC encoding [1] [2]. However, previous works [1][2] are all for CAVLC (Context Based Adaptive Variable Length Coding) based RD optimization process and are not accurate for CABAC (Context Based Adaptive Binary Arithmetic Coding) based RD optimization process. As known, compared with CAVLC, CABAC entropy coding provides higher coding efficiency at average bit rate saving of 9%-14% [3]. Hence, it is desirable to find a fast bit estimation method that is suitable for RD optimization with CABAC entropy coding. In this paper, we present such kind of fast bit estimation method. The experiments show that the proposed method can reduce around 30% of the RD optimization time averagely while maintaining the similar coding performance comparing to that of original H.264/AVC with RD optimization enabled.
The role of MVU estimator and CRB in binary composite hypothesis test
Authors: Ali Ghobadzadeh, Sayed Jalal Zahabi, Ali A. Tadaion
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 2 (2009)

This work presents a new perspective to the relationship between the composite binary hypothesis test and the estimation of its unknown parameters, i.e, the Uniformly Most Powerful (UMP) test and the Minimum Variance and Unbiased Estimator(MVUE). We show that for the one-sided binary composite hypothesis test, if the UMP test exists, it is nothing but comparing the MVUE for the unknown parameter with a threshold. The paper tries to make a link between the Cramer Rao Bound (CRB) in estimation theory and the UMP performance bound in detection theory. In addition to the intrinsic theoretical interest of such relationship discussed in the paper, it leads us to proposing a novel detection method. For such problems in which the UMP test does not exist, we suggest using a good estimator of the unknown parameter as the decision statistic. The simulation results confirm the idea that the closer we get to the CRB in estimating the unknown parameter, the more we get near to the UMP performance bound in detection.
Automated reconstruction of the cerebral cortex in multiple sclerosis patients
Authors: N. Shiee, P.-L. Bazin, Daniel S. Reich, D. L. Pham
Venue: Proceedings of the Sixth IEEE international conference on Symposium on Biomedical Imaging: From Nano to Macro (2009)

Although cortical atrophy in multiple sclerosis (MS) has been reported in the literature, most cortical reconstruction techniques do not account for lesions. In this work, we propose an automated pipeline for cortical reconstruction from magnetic resonance brain images with MS lesions. The pipeline extends previously well validated methods to allow for the presence of lesions and to accommodate multichannel imaging. We validate this approach on simulated and real images. Application of the pipeline to 103 MS brains produces thickness measurements that agree well with the literature.
MISO broadcast channel with user-cooperation and limited feedback
Authors: Hyukjoon Kwon, John M. Cioffi
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

This paper presents a user-cooperation scheme with limited feedback in a broadcast channel. The proposed scheme allows mobile stations to forward received messages over finite-capacity orthogonal channels, known as conferencing. In addition, the proposed scheme jointly uses the feedback from mobile stations to mitigate multi-user interference by choosing the best beamforming vectors from a finite-sized codebook. As a result, a multi-user broadcast channel is located between a point-to-point multiple-input multiple-output channel and a multi-user multiple-input single-output channel. The former is where full coherent cooperation among receiver antennas is allowed, and the latter is where no cooperation among mobile stations is assumed. Then, this paper analyzes the relation between the amounts of user-cooperation and limited feedback, and shows a trade-off between the relative use of each. Simulation results verify the advantage of cooperation and feedback as complementary technologies in wireless cellular networks.