检索结果-内蒙古大学图书馆

IEEE International Conference on Computer Design: VLSI in Computers and Processors, (ICCD)

作者： Ritajit Majumdar Susmita Sur-Kolay Advanced Computing and Microelectronics Unit Indian Statistical Institute Kolkata

ISBN: (数字)9781728197104

ISBN: (纸本)9781728197111

Large-scale quantum computers mandate error correction and fault tolerance. Due to constraints on the number of qubits, fault tolerance is difficult to achieve in near-term quantum systems. Therefore, error correction should require minimal resources. Gates in the near-term devices are also noisy. Quantum error correction code blocks built with these noisy gates can inject further error in the circuit. The goals for error correction in near-term systems are as follows: (i) using a small number of qubits for encoding, and (ii) keeping cost of circuits for encoding and decoding low. In this paper, we propose two techniques to achieve these mutually orthogonal goals. For a binary quantum system we propose an error estimation method that can aid in reducing the number of error correcting blocks via sparse scheduling. For ternary quantum systems, we propose an approximate code that can correct errors with high probability while significantly reducing the circuit cost. These techniques are expected to be helpful for error mitigation in near-term systems in the absence of fault tolerance.

关键词： Fault tolerance Fault tolerant systems Qubit Logic gates Error correction Error correction codes Noise measurement

来源：评论

学校读者我要写书评

暂无评论

Optimal Error Correcting Code For Ternary Quantum Systems

arXiv

引用

arXiv 2019年

作者： Majumdar, Ritajit Sur-Kolay, Susmita Advanced Computing & Microelectronics Unit Indian Statistical Institute India

Multi-valued quantum systems can store more information than binary ones for a given number of quantum states. For reliable operation of multi-valued quantum systems, error correction is mandated. In this paper, we propose a 5-qutrit quantum error correcting code and provide its stabilizer formulation. Since 5 qutrits are necessary to correct a single error, our proposed code is optimal in the number of qutrits. We prove that the error model considered in this paper spans the entire (3 × 3) operator space. Therefore, our proposed code can correct any single error on the codeword. This code outperforms the previous 9-qutrit code in (i) the number of qutrits required for encoding, (ii) our code can correct any arbitrary (3 × 3) error, (ii) our code can readily correct bit errors in a single step as opposed to the two-step correction used previously, and (iii) phase error correction does not require correcting individual subspaces. Copyright © 2019, The Authors. All rights reserved.

关键词： Many valued logics

来源：评论

学校读者我要写书评

暂无评论

Quantum error correction for non-maximally entangled states

arXiv

引用

arXiv 2017年

作者： Majumdar, Ritajit Sur-Kolay, Susmita Advanced Computing and Microelectronics Unit Indian Statistical Institute India

Quantum states have high affinity for errors and hence error correction is of utmost importance to realise a quantum computer. Laflamme showed that 5 qubits are necessary to correct a single error on a qubit. In a Pauli error model, four different types of errors can occur on a qubit. Maximally entangled states are orthogonal to each other and hence can be uniquely distinguished by a measurement in the Bell basis. Thus a measurement in Bell basis and a unitary transformation is sufficient to correct error in Bell states. However, such a measurement is not possible for non-maximally entangled states. In this work we show that the 16 possible errors for a non-maximally entangled two qubit system map to only 8 distinct error states. Hence, it is possible to correct the error without perfect knowledge of the type of error. Furthermore, we show that the possible errors can be grouped in such a way that all 4 errors can occur on one qubit, whereas only bit flip error can occur on the second qubit. As a consequence, instead of 10, only 8 qubits are sufficient to correct a single error. We propose an 8-qubit error correcting code to correct a single error in a non-maximally entangled state. We further argue that for an n-qubit non-maximally entangled state of the form a |0)0n+ ß |1)0n, it is always possible to correct a single error with fewer than 5n qubits, in fact only 3n + 2 qubits suffice. Copyright © 2017, The Authors. All rights reserved.

关键词： Quantum entanglement

来源：评论

学校读者我要写书评

暂无评论

Editorial

引用

Microprocessors and Microsystems 2004年第8期28卷 401-402页

作者： Jayasree Dattagupta Nabanita Das Advanced Computing and Microelectronics Unit Indian Statistical Institute Kolkata 700-108 India

来源：评论

学校读者我要写书评

暂无评论

Analyzing the Effect of Soft Handover on Handover Performance Evaluation Metrics under Load Condition

Analyzing the Effect of Soft Handover on Handover Performanc...

引用

作者： Panigrahy, Nitish K. Ghosh, Sasthi C. College of Information and Computer Sciences University of Massachusetts AmherstMA01003-9264 United States Advanced Computing and Microelectronics Unit Indian Statistical Institute Kolkata700108 India

With increasing popularity of wireless local area network (WLAN) and emerging real-time applications, seamless mobility has become one of the primary concerns. Hence, the choice of a proper handover algorithm is of utmost importance. Various performance evaluation metrics for handover algorithms have been proposed in this regard. We argue that in a multiple access point (AP) scenario, the load on each of the APs, the requested data rate of the mobile terminal, and the soft handover have significant impact on these metrics. In this paper, we present an analytical framework to measure various handover performance evaluation metrics under both load condition and soft handover for a specific data rate request. Our approach is based on finding the circular region centered around an AP within which the requested data rate can be satisfied. We have considered WLAN usage efficiency, handover failure probability, and unnecessary handover probability as evaluation metrics. We have analyzed the impact of load and soft handover on these metrics. The impact of velocity on these metrics has also been analyzed. We also have derived lower bounds on both handover failure probability and unnecessary handover probability by formulating the problem into three circle intersection problem. The circular coverage assumption used in the framework is also validated through simulation. © 1967-2012 IEEE.

关键词： Efficiency

来源：评论

学校读者我要写书评

暂无评论

A Fast Community-based Approach for Discovering Anomalies in Evolutionary Networks 14

A Fast Community-based Approach for Discovering Anomalies in...

引用

14th International Conference on COMmunication Systems and NETworkS, COMSNETS 2022

作者： Ghoshal, Arnab Kumar Das, Nabanita Das, Soham Asutosh College Department of Computer Science Kolkata India Indian Statistical Institute Advanced Computing and Microelectronics Unit Kolkata India Microsoft Corporation RedmondWA United States

ISBN: (纸本)9781665421041

Many real-life networks such as social networks, biological networks, citation networks etc., are temporally evolving by nature. In general, the evolution takes place gradually with time. But occasionally, the nodes may exhibit anomalous behavior that is to be detected and reported in real time. In this work, for anomaly detection in evolutionary networks, an action based approach is followed taking into account the network topology. The network is represented as a temporal stream of weighted graphs, where edge weights stand for frequency or power of actions. A new definition of anomaly score is introduced for nodes based on its action history. To reduce the search space, the community structure of the graph is exploited. It has been shown that only the nodes having multiple community membership are enough to detect anomaly in a temporally evolving network with overlapping community structure. To the best of our knowledge, this is the first work to exploit the overlapping community structure of an evolutionary network to identify the graph snapshots containing anomalous events. Experimental studies on both synthetic and real-world evolutionary networks show that the proposed technique achieves almost 16% improvement in F-Score compared to the state-of-the-art algorithms. Moreover, parallel implementation of the proposed technique results nearly 10× speedup making it suitable for real time computation of anomaly in evolutionary networks. © 2022 IEEE.

关键词： Anomaly detection

来源：评论

学校读者我要写书评

暂无评论

Minimal degenerate CSS quantum code with low cost circuit

arXiv

引用

arXiv 2019年

作者： Majumdar, Ritajit Sur-Kolay, Susmita Advanced Computing and Microelectronics Unit Indian Statistical Institute Kolkata India

Error correction is of utmost necessity for large-scale quantum computing. Quantum error correcting codes can be degenerate, if more than one type of error can map the input state to the same error state. In this paper, we propose a 6-qubit degenerate CSS code. We show that our proposed code can correct a single bit flip error, but arbitrarily many phase flip errors occurring on the codeword. Furthermore, it follows from a bound on CSS codes that the proposed code is the minimal binary CSS code which can encode a single qubit of information. We also perform a comparative study of the gate count required for a fault tolerant decomposition of the error correction circuit for the proposed code, with that for the existing 9-qubit, 7-qubit and 5-qubit binary QEC codes. Our results show, on an average over the different technologies a savings of 98.14% in the gate count for the proposed code over that for the 5-qubit code. Significant improvement of around 50% in gate count is also obtained when compared to those for the 9-qubit and 7-qubit codes. Copyright © 2019, The Authors. All rights reserved.

关键词： Error correction

来源：评论

学校读者我要写书评

暂无评论

Non-optimal is Good! Resource Allocation in Presence of Dynamic Obstacles in D2D Networks

Non-optimal is Good! Resource Allocation in Presence of Dyna...

引用

Conference on Local Computer Networks (LCN)

作者： Rathindra Nath Dutta Sasthi C. Ghosh Advanced Computing and Microelectronics Unit Indian Statistical Institute Kolkata India

To cope with high bandwidth demands of modern applications, device-to-device (D2D) communications using millimeter-wave (mmWave) signals are being harnessed. The major challenge of mmWave signals is that they require a strict, obstacle-free line-of-sight communication. Static obstacles are easier to avoid; dynamic obstacles pose the main hurdle, their movement not being known. In this work, we propose a way to learn link blockages due to dynamic obstacles, using the link activation history. For this, one might have to explore non-optimal link activations. This ensures that all links are tried a sufficient number of times, ensuring adequate knowledge about link failures, thus creating an exploration-exploitation dilemma. To this end, we propose a systematic way of exploring such non-optimal channel allocations, so that the number of link failures is minimized. Given the hardness of this problem, we devise a greedy solution, and show its effectiveness over existing strategies through simulations.

关键词：

来源：评论

学校读者我要写书评

暂无评论

A Randomized Algorithm for Joint Power and Channel Allocation in 5G D2D Communication

A Randomized Algorithm for Joint Power and Channel Allocatio...

引用

IEEE International Symposium on Network computing and Applications

作者： Subhankar Ghosal Sasthi C. Ghosh Advanced Computing and Microelectronics Unit Indian Statistical Institute Kolkata India

We formulate the joint power and channel allocation problem (JPCAP) for device to device (D2D) communication as a cost minimization problem, where cost is defined as a linear combination of the number of channels used and total power requirement. We first show that JPCAP is NP-hard and then propose a greedy channel and power allocation (GCPA) algorithm to assign channels and powers to the links. We design GCPA in such a fashion that there exists an order of the links for which it produces optimum solution. Finally using GCPA we develop a randomized algorithm (RA) that increase the optimum hitting probability by an exponential factor of total number of links. Through simulation, we evaluate the performance of RA and show that RA outperforms an existing approach.

关键词： Device-to-device communication Interference Resource management Receivers Transmitters Channel allocation Signal to noise ratio

来源：评论

学校读者我要写书评

暂无评论

An RIS Deployment Strategy to Overcome Static Obstacles in Millimeter Wave D2D Communication

An RIS Deployment Strategy to Overcome Static Obstacles in M...

引用

IEEE International Symposium on Network computing and Applications

作者： Souvik Deb Sasthi C. Ghosh Advanced Computing & Microelectronics Unit Indian Statistical Institute Kolkata India

ISBN: (纸本)9781665495516

Use of millimeter waves for short range device to device (D2D) communication is one of the most promising ways to provide high data rates. But millimeter waves are susceptible to blockages due to high penetration losses and hence require almost a line of sight (LoS) communication to provide such high data rates. When the direct LoS of a pair of devices is blocked by an obstacle, a reconfigurable intelligent surfaces (RIS) in the vicinity can be exploited to bypass the obstacle and achieve an indirect LoS between them. In this paper, we develop a strategy for placing minimum number of RISs in an environment filled with obstacles such that any pair of devices in the environment who does not have direct LoS can communicate via these RISs by establishing an indirect LoS. We convert this RIS placement problem to a set cover problem and give a greedy algorithm to get a near optimal but practical solution. This is done as a preprocessing step before the actual devices are deployed in the region. Next we present a strategy which knowing the actual deployment of the devices, selects a subset of the deployed RISs for operation together with their channel coefficients and phase shifts such that the system sum throughput of the devices is maximised. Finally simulation results show that strategically placed RISs can significantly improve system throughput in comparison to the existing deployment strategies.

关键词： Performance evaluation Greedy algorithms Millimeter wave devices Surface waves Simulation Reconfigurable intelligent surfaces Throughput

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：