Shilin Zhu

Flexible Availability-Aware Differentiated Protection in Software-Defined Elastic Optical Networks

Availability-aware service provisioning tries to satisfy the availability requirements of clients on demand and can improve the resource efficiency in optical networks. This paper studies the problem of flexible availability-aware differentiated protection (ADP) in elastic optical networks (EONs). We first consider the unique features in EONs, e.g., flexible spectrum allocation and bandwidth-squeezed protection, describe the problem of ADP, and present a theoretical analysis on service availability. Then, we develop an ADP algorithm that can change the path protection scheme to adapt to different service availability requirements. An availability-aware backup reprovisioning strategy is also proposed as a supplement of the ADP algorithm to further improve the protection efficiency. We also discuss the system design for OpenFlow-based software-defined EON (SD-EON) framework to facilitate the ADP scheme. Finally, to demonstrate the overall design, we construct an SD-EON control plane testbed that consists of 14 standalone nodes, implement the proposed algorithms in the OpenFlow controller, and perform experiments to evaluate their performance. The results indicate that the system performs well, and the proposed algorithms can reduce blocking probability effectively without sacrificing the service availability of requests.

On Spectrum Efficient Failure-Independent Path Protection p -Cycle Design in Elastic Optical Networks

High spectrum efficiency and fast restoration speed are highly desired for survivable elastic optical networks (EONs). In this paper, we take the advantages of failure-independent path-protecting preconfigured cycles (FIPP p-cycles) and investigate how to realize spectrum efficient resilience design with them. We first study the problem of offline service provisioning with FIPP p-cycles. We formulate an integer linear programming model and prove that the problem is NP hard. Then, several time-efficient heuristics are designed for FIPP p-cycle formulation and related routing, modulation format, and spectrum assignment. Extensive simulations on offline provisioning verify that the heuristics can obtain near-optimal solutions. Next, we consider online service provisioning with FIPP p-cycles in dynamic EONs. In order to overcome the decrease of protection efficiency during dynamic network operation, we propose a p-cycle reconfiguration scheme to reoptimize protection structures on-the-fly. Simulation results demonstrate that the proposed algorithms can improve spectrum efficiency and reduce bandwidth blocking probability simultaneously.

MICROST: A mixed approach for heart rate monitoring during intensive physical exercise using wrist-type PPG Signals

The performance of heart rate (HR) monitoring using wrist-type photoplethysmographic (PPG) signals is strongly influenced by motion artifacts (MAs), since the intensive physical exercises are common in real world. Few works focus on this study so far because of unsatisfying quality of corrupted PPG signals. In this paper, we propose an accurate and efficient strategy, named MICROST, which estimates heart rate based on a mixed approach. The MICROST framework is designed as a MIxed algorithm which consists of acceleration Classification (AC), fiRst-frame prOcessing and heuriStic Tracking. Experimental results using recordings from 12 subjects during fast running and intensive movement showed the average absolute error of heart rate estimation was 2.58 beat per minute (BPM), and the Pearson correlation between the estimates and the ground-truth of heart rate was 0.988. We discuss our approach in real time to face the applications of wearable devices such as smart-watches in reality.

SMART precision cancer medicine: a FHIR-based app to provide genomic information at the point of care

BACKGROUND Precision cancer medicine (PCM) will require ready access to genomic data within the clinical workflow and tools to assist clinical interpretation and enable decisions. Since most electronic health record (EHR) systems do not yet provide such functionality, we developed an EHR-agnostic, clinico-genomic mobile app to demonstrate several features that will be needed for point-of-care conversations. METHODS Our prototype, called Substitutable Medical Applications and Reusable Technology (SMART)® PCM, visualizes genomic information in real time, comparing a patients diagnosis-specific somatic gene mutations detected by PCR-based hotspot testing to a population-level set of comparable data. The initial prototype works for patient specimens with 0 or 1 detected mutation. Genomics extensions were created for the Health Level Seven® Fast Healthcare Interoperability Resources (FHIR)® standard; otherwise, the prototype is a normal SMART on FHIR app. RESULTS The PCM prototype can rapidly present a visualization that compares a patients somatic genomic alterations against a distribution built from more than 3000 patients, along with context-specific links to external knowledge bases. Initial evaluation by oncologists provided important feedback about the prototypes strengths and weaknesses. We added several requested enhancements and successfully demonstrated the app at the inaugural American Society of Clinical Oncology Interoperability Demonstration; we have also begun to expand visualization capabilities to include cancer specimens with multiple mutations. DISCUSSION PCM is open-source software for clinicians to present the individual patient within the population-level spectrum of cancer somatic mutations. The app can be implemented on any SMART on FHIR-enabled EHRs, and future versions of PCM should be able to evolve in parallel with external knowledge bases.

Availability-aware service provisioning in SD-EON-based inter-datacenter networks

The tremendous transmission capacity and flexible spectrum allocation scheme make elastic optical networks (EONs) one of the most promising infrastructures for constructing the interconnection in datacenter (DC) networks. Meanwhile, as DC traffics exhibit highly dynamic and heterogeneous features, differentiated service provisioning schemes are desired. In this paper, we take the advantage of centralized network control and management provided by the software-defined elastic optical networks (SD-EONs) and investigate availability-aware service provisioning in SD-EON-based inter-datacenter (inter-DC) networks. We first describe the problem of availability-aware service provisioning in SD-EON-based inter-DC networks and present the theoretical analysis for service availability. Then, we propose an availability-aware service provisioning algorithm (ASP) that leverages different path protection schemes to satisfy different service availability requirements. A service downgrading (SD) strategy is also designed as a supplement of ASP to further improve its performance. Simulation results show that the proposed ASP-SD algorithm can effectively improve the spectrum efficiency without sacrificing availability.

On efficient protection design for dynamic multipath provisioning in elastic optical networks

Multipath provisioning (MPP) in elastic optical networks (EONs) can improve the network performance effectively. In this paper, we study the protection schemes for MPP to ensure 100% restoration against single-link failures. We design three algorithms, namely, Instant-ILP, PWCE-MPP and mPWCEMPP. The first one leverages a simple integer linear programming (ILP) model to design the optimal working-backup structure for each request instantly, while the rest two utilize protected working capacity envelop (PWCE) and spectrum planning to further reduce bandwidth blocking probability (BBP). Moreover, mPWCE-MPP considers the differences among working and backup paths, and ensures that the maximum path-difference (MPD) of a request will not increase dramatically in restoration. Simulation results show that mPWCE-MPP can obtain the best trade-off between BBP and average MPD.

Accelerating Mobile Web Loading Using Cellular Link Information

Despite the 4G LTEs 10X capacity improvement over 3G, mobile Web loading latency remains a major issue that hampers user experience. The root cause lies in the inefficient transport-layer that underutilizes LTE capacity, due to high channel dynamics, wireless link losses, and insufficient application traffic to propel the bandwidth probing. In this paper, we propose Cellular Link-Aware Web loading (CLAW), which boosts mobile Web loading using a physical-layer informed transport protocol. CLAW harnesses the limited PHY-layer statistics available on LTE phones to quantitatively model the LTE channel resource utilization, which is then translated into a transport window that best fits the bandwidth. Consequently, CLAW can estimate and fully utilize the available bandwidth almost within one RTT. In addition, CLAW can precisely differentiate LTE wireless loss from congestion loss, and identify the rare cases when the wireline backhaul becomes the bottleneck. We have prototyped CLAW on commodity LTE phones. Across a wide range of experimental settings, CLAW consistently reduces Web loading latency by more than 30%, compared to classical TCP variants and state-of-the-art congestion controls for cellular networks.

Availability-aware service provisioning in EONs: How efficient will FIPP-p-cycles be?

We propose to realize availability-aware service provisioning in EONs with FIPP-p-cycles and bandwidth-squeezed restoration. Simulation results show that the proposed schemes are more reliable and spectrum-efficient than the existing approach.

Service Provisioning with Energy-Aware Regenerator Allocation in Multi-Domain EONs

As multi-domain elastic optical networks (EONs) can enhance network scalability, extend service reach, and accommodate the inter-operability issues, it is very relevant to consider them in practical network operations. In this work, we study the problem of how to achieve energy-aware service provisioning in a multi-domain EON, where the optoelectronic regenerators only exist in border nodes. We consider dynamic lightpath requests and propose two algorithms, i.e., the greedy regenerator allocation (GRA) and the set-cover based regenerator allocation (STC), to realize the joint optimization of routing, modulation and spectrum assignment (RMSA) and regenerator allocation. The algorithms are evaluated with extensive simulations that use multi-domain EONs built with different regenerator placement strategies. The results verify that GRA and STC outperform the existing algorithm for energy-aware multi-domain service provisioning, and STC achieves the best performance in terms of both blocking probability and power efficiency.

Automating Visual Privacy Protection Using a Smart LED

The ubiquity of mobile camera devices has been triggering an outcry of privacy concerns, whereas privacy protection still relies on the cooperation of the photographer or camera hardware, which can hardly be guaranteed in practice. In this paper, we introduce LiShield, which automatically protects a physical scene against photographing, by illuminating it with smart LEDs flickering in specialized waveforms. We use a model-driven approach to optimize the waveform, so as to ensure protection against the (uncontrollable) cameras and potential image-processing based attacks. We have also designed mechanisms to unblock authorized cameras and enable graceful degradation under strong ambient light interference. Our prototype implementation and experiments show that LiShield can effectively destroy unauthorized capturing while maintaining robustness against potential attacks.