The Experts below are selected from a list of 33411 Experts worldwide ranked by ideXlab platform

Muris Sarajlić - One of the best experts on this subject based on the ideXlab platform.

  • DeCentralized Massive MIMO Processing Exploring Daisy-Chain Architecture and Recursive Algorithms
    IEEE Transactions on Signal Processing, 2020
    Co-Authors: Jesús Rodríguez Sánchez, Fredrik Rusek, Ove Edfors, Muris Sarajlić
    Abstract:

    Algorithms for Massive MIMO uplink detection and downlink precoding typically rely on a Centralized approach, by which baseband data from all antenna modules are routed to a Central Node in order to be processed. In the case of Massive MIMO, where hundreds or thousands of antennas are expected in the base-station, said routing becomes a bottleneck since interconnection throughput is limited. This paper presents a fully deCentralized architecture and an algorithm for Massive MIMO uplink detection and downlink precoding based on the Coordinate Descent (CD) method, which does not require a Central Node for these tasks. Through a recursive approach and very low complexity operations, the proposed algorithm provides a good trade-off between performance, interconnection throughput and latency. Further, our proposed solution achieves significantly lower interconnection data-rate than other architectures, enabling future scalability.

Akira Miyauchi - One of the best experts on this subject based on the ideXlab platform.

  • prognosis of patients with papillary thyroid carcinoma located in one lobe showing lateral Node metastasis in the contralateral but not ipsilateral compartment
    Journal of Thyroid Research, 2012
    Co-Authors: Yasuhiro Ito, Takuya Higashiyama, Yuuki Takamura, Akihiro Miya, Kaoru Kobayashi, Akira Miyauchi
    Abstract:

    Papillary thyroid carcinoma (PTC) frequently metastasizes to the lymph Node in lateral compartment, which can often be detected on preoperative ultrasonography (N1b). However, PTC located in one lobe showing contralateral but not ipsilateral N1b is not common. We analyzed the clinicopathological features and prognosis of 13 patients with PTC limited in one lobe showing contralateral but not ipsilateral N1b. Sizes of the primary lesions ranged from 0.8 cm to 3.0 cm and only 2 tumors showed extrathyroid extension. Metastatic lateral Node measured from 0.6 to 3.1 cm. Ten patients showed pathological Central Node metastasis and 5 had minute PTC lesions in the contralateral lobe. However, 3 patients did not show either of these. None of the patients have developed carcinoma recurrence or died of carcinoma to date. Taken together, PTC located in one lobe with contralateral but not ipsilateral N1b is rare and generally shows an indolent behavior. Although most patients had Central Node metastasis and/or minute PTC lesions in the contralateral lobe, it is also possible for carcinoma cells to metastasize directly from primary lesions to the contralateral lateral Node. Total thyroidectomy with Central Node dissection and therapeutic MND of the contralateral compartment may be an acceptable surgical design and bilateral MND might not be mandatory.

  • clinical significance of lymph Node metastasis of thyroid papillary carcinoma located in one lobe
    World Journal of Surgery, 2006
    Co-Authors: Tomoo Jikuzono, Kanji Kuma, Shuji Asahi, Chisato Tomoda, Takuya Higashiyama, Yuuki Takamura, Akihiro Miya, Kaoru Kobayashi, Fumio Matsuzuka, Akira Miyauchi
    Abstract:

    Background: Previous studies have shown that lymph Node metastasis can be of prognostic value. In this study, we investigated the clinical significance of Node metastasis focusing on metastasis in the Central compartment for patients with papillary carcinoma located in one lobe. Patients and Methods: We investigated the frequency of lymph Node metastasis in 759 patients with papillary carcinoma to determine whether and how such metastasis affects disease-free survival (DFS). Results: Central Node metastasis was observed in 63% of patients, and the frequency was increased in relation to tumor size. The frequency of lateral Node metastasis was 62.0%, which was also directly related to tumor size. On multivariate analysis of cases showing tumor larger than 1 cm, Central Node metastasis was recognized as an independent prognostic factor of DFS. The frequency of metastasis to the paratracheal Nodes contralateral to the tumor was drastically elevated for tumors larger than 1 cm, but metastasis to this region did not independently predict worse DFS. Conclusion: Central Node metastasis independently predicts a worse DFS for patients with papillary carcinoma larger than 1 cm.

  • clinical significance of metastasis to the Central compartment from papillary microcarcinoma of the thyroid
    World Journal of Surgery, 2006
    Co-Authors: Yasuhiro Ito, Kanji Kuma, Chisato Tomoda, Yuuki Takamura, Akihiro Miya, Kaoru Kobayashi, Fumio Matsuzuka, Takashi Uruno, Akira Miyauchi
    Abstract:

    We previously demonstrated that for papillary microcarcinoma (PMC), (1) patients with lateral lymph Node metastasis detected on preoperative ultrasonography (US) are more likely to develop recurrence, and (2) dissection of the lateral compartment does not improve the prognosis of patients without US-detectable lateral metastasis. In this study, we focused on metastasis from PMC to the Central compartment. We investigated the clinical significance of lymph Nodes in the Central compartment using the same series of 600 patients as used in the previous study. Ultrasound-diagnosed Central Node metastasis could be found in 30 patients (20.0%). Although the specificity of US for detecting Central Node metastasis was 99.1%, sensitivity was only 10.9%. Neither US-diagnosed nor pathologically confirmed Central Node metastasis affected the disease-free survival (DFS) rate of PMC patients. Furthermore, in cases where PMC was located only in one lobe, Central Node dissection in the contralateral lobe did not improve the DFS rate. These findings suggest that, for PMC, (1) US is an insensitive technique for detecting the Central Node metastasis, (2) the presence of Central Node metastasis is unrelated to DFS of patients, and (3) when performing lobectomy for PMC involving only one lobe, dissection of the Central compartment in the contralateral lobe is optional.

Jesús Rodríguez Sánchez - One of the best experts on this subject based on the ideXlab platform.

  • DeCentralized Massive MIMO Processing Exploring Daisy-Chain Architecture and Recursive Algorithms
    IEEE Transactions on Signal Processing, 2020
    Co-Authors: Jesús Rodríguez Sánchez, Fredrik Rusek, Ove Edfors, Muris Sarajlić
    Abstract:

    Algorithms for Massive MIMO uplink detection and downlink precoding typically rely on a Centralized approach, by which baseband data from all antenna modules are routed to a Central Node in order to be processed. In the case of Massive MIMO, where hundreds or thousands of antennas are expected in the base-station, said routing becomes a bottleneck since interconnection throughput is limited. This paper presents a fully deCentralized architecture and an algorithm for Massive MIMO uplink detection and downlink precoding based on the Coordinate Descent (CD) method, which does not require a Central Node for these tasks. Through a recursive approach and very low complexity operations, the proposed algorithm provides a good trade-off between performance, interconnection throughput and latency. Further, our proposed solution achieves significantly lower interconnection data-rate than other architectures, enabling future scalability.

Kanji Kuma - One of the best experts on this subject based on the ideXlab platform.

  • clinical significance of lymph Node metastasis of thyroid papillary carcinoma located in one lobe
    World Journal of Surgery, 2006
    Co-Authors: Tomoo Jikuzono, Kanji Kuma, Shuji Asahi, Chisato Tomoda, Takuya Higashiyama, Yuuki Takamura, Akihiro Miya, Kaoru Kobayashi, Fumio Matsuzuka, Akira Miyauchi
    Abstract:

    Background: Previous studies have shown that lymph Node metastasis can be of prognostic value. In this study, we investigated the clinical significance of Node metastasis focusing on metastasis in the Central compartment for patients with papillary carcinoma located in one lobe. Patients and Methods: We investigated the frequency of lymph Node metastasis in 759 patients with papillary carcinoma to determine whether and how such metastasis affects disease-free survival (DFS). Results: Central Node metastasis was observed in 63% of patients, and the frequency was increased in relation to tumor size. The frequency of lateral Node metastasis was 62.0%, which was also directly related to tumor size. On multivariate analysis of cases showing tumor larger than 1 cm, Central Node metastasis was recognized as an independent prognostic factor of DFS. The frequency of metastasis to the paratracheal Nodes contralateral to the tumor was drastically elevated for tumors larger than 1 cm, but metastasis to this region did not independently predict worse DFS. Conclusion: Central Node metastasis independently predicts a worse DFS for patients with papillary carcinoma larger than 1 cm.

  • clinical significance of lymph Node metastasis of thyroid papillary carcinoma located in one lobe
    World Journal of Surgery, 2006
    Co-Authors: Yasuhiro Ito, Tomoo Jikuzono, Shuji Asahi, Chisato Tomoda, Takuya Higashiyama, Yuuki Takamura, Akihiro Miya, Kaoru Kobayashi, Fumio Matsuzuka, Kanji Kuma
    Abstract:

    Previous studies have shown that lymph Node metastasis can be of prognostic value. In this study, we investigated the clinical significance of Node metastasis focusing on metastasis in the Central compartment for patients with papillary carcinoma located in one lobe. We investigated the frequency of lymph Node metastasis in 759 patients with papillary carcinoma to determine whether and how such metastasis affects disease-free survival (DFS). Central Node metastasis was observed in 63% of patients, and the frequency was increased in relation to tumor size. The frequency of lateral Node metastasis was 62.0%, which was also directly related to tumor size. On multivariate analysis of cases showing tumor larger than 1 cm, Central Node metastasis was recognized as an independent prognostic factor of DFS. The frequency of metastasis to the paratracheal Nodes contralateral to the tumor was drastically elevated for tumors larger than 1 cm, but metastasis to this region did not independently predict worse DFS. Central Node metastasis independently predicts a worse DFS for patients with papillary carcinoma larger than 1 cm.

  • clinical significance of metastasis to the Central compartment from papillary microcarcinoma of the thyroid
    World Journal of Surgery, 2006
    Co-Authors: Yasuhiro Ito, Kanji Kuma, Chisato Tomoda, Yuuki Takamura, Akihiro Miya, Kaoru Kobayashi, Fumio Matsuzuka, Takashi Uruno, Akira Miyauchi
    Abstract:

    We previously demonstrated that for papillary microcarcinoma (PMC), (1) patients with lateral lymph Node metastasis detected on preoperative ultrasonography (US) are more likely to develop recurrence, and (2) dissection of the lateral compartment does not improve the prognosis of patients without US-detectable lateral metastasis. In this study, we focused on metastasis from PMC to the Central compartment. We investigated the clinical significance of lymph Nodes in the Central compartment using the same series of 600 patients as used in the previous study. Ultrasound-diagnosed Central Node metastasis could be found in 30 patients (20.0%). Although the specificity of US for detecting Central Node metastasis was 99.1%, sensitivity was only 10.9%. Neither US-diagnosed nor pathologically confirmed Central Node metastasis affected the disease-free survival (DFS) rate of PMC patients. Furthermore, in cases where PMC was located only in one lobe, Central Node dissection in the contralateral lobe did not improve the DFS rate. These findings suggest that, for PMC, (1) US is an insensitive technique for detecting the Central Node metastasis, (2) the presence of Central Node metastasis is unrelated to DFS of patients, and (3) when performing lobectomy for PMC involving only one lobe, dissection of the Central compartment in the contralateral lobe is optional.

Antonio Ortega - One of the best experts on this subject based on the ideXlab platform.

  • energy efficient data representation and routing for wireless sensor networks based on a distributed wavelet compression algorithm
    Information Processing in Sensor Networks, 2006
    Co-Authors: Alexandre Ciancio, Antonio Ortega, Sundeep Pattem, Bhaskar Krishnamachari
    Abstract:

    We address the problem of energy consumption reduction for wireless sensor networks, where each of the sensors has limited power and acquires data that should be transmitted to a Central Node. The final goal is to have a reconstructed version of the data measurements at the Central Node, with the sensors spending as little energy as possible, for a given data reconstruction accuracy. In our scenario, sensors in the network have a choice of different coding schemes to achieve varying levels of compression. The compression algorithms considered are based on the lifting factorization of the wavelet transform, and exploit the natural data flow in the network to aggregate data by computing partial wavelet coefficients that are refined as data flows towards the Central Node. The proposed algorithm operates by first selecting a routing strategy through the network. Then, for each route, an optimal combination of data representation algorithms i.e. assignment at each Node, is selected. A simple heuristic is used to determine the data representation technique to use once path merges are taken into consideration. We demonstrate that by optimizing the coding algorithm selection the overall energy consumption can be significantly reduced when compared to the case when data is just quantized and forwarded to the Central Node. Moreover, the proposed algorithm provides a tool to compare different routing techniques and identify those that are most efficient overall, for given Node locations. We evaluate the algorithm using both a second-order autoregressive (AR) model and empirical data from a real wireless sensor network deployment.

  • a distributed wavelet compression algorithm for wireless multihop sensor networks using lifting
    International Conference on Acoustics Speech and Signal Processing, 2004
    Co-Authors: Alexandre Ciancio, Antonio Ortega
    Abstract:

    We address the problem of compression for wireless sensor networks, where each of the sensors has limited power, and acquires data that should be sent to a Central Node. The final goal is to have a reconstructed version of the sampled field at the Central Node, with the sensors spending as little energy as possible. We propose a distributed compression algorithm for multihop, distributed sensor networks based on the lifting factorization of the wavelet transform that exploits the natural data flow in the network to aggregate data by computing partial wavelet coefficients that are refined as the data flows towards the Central Node. A key result of our work is that by performing partial computations we greatly reduce unnecessary transmission, significantly reducing the overall energy consumption.