lprof: A Non-intrusive Request Flow Profiler for Distributed Systems

by Jinyoung Choi on 2015-08-24 00:00:00

* 동영상 강의로 진행됩니다. (총 2편) Date: 2015. 08. 25. (Tue) 10:30 A.M. Locate: EB5. 533 Continue reading →

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ScreenPass: secure password entry on touchscreen devices

by Jinyoung Choi on 2015-08-17 10:57:29

Date : 2015. 08. 18. (Tue) 10:30 A.M. Locate : EB5. 533 Presenter : Jinyoung Choi   Title : ScreenPass: secure password entry on touchscreen devices Author : Dongtao Liu, Eduardo Cuervo, Valentin Pisto, Ryan Scudellari, Landon P. Cox    Abstract   Users routinely access cloud services through third-party apps on smartphones by giving apps login credentials (i.e., a username and password). Unfortunately, users have no assurance that their apps will properly handle this sensitive information. In this paper, we describe the design and implementation of ScreenPass, which significantly improves the security of passwords on touchscreen devices. ScreenPass secures passwords by ensuring that they are entered securely, and uses taint-tracking to monitor where apps send password data. The primary technical challenge addressed by ScreenPass is guaranteeing that trusted code is always aware of when a user is entering a password. ScreenPass ... Continue reading →

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Decoupling Cores, Kernels, and Operating Systems

by Jinyoung Choi on 2015-08-12 20:29:58

* 동영상 강의로 진행됩니다. (총 2편)   Date : 2015. 08. 21. (Fri) 10:30 A.M. Locate : EB5. 533   Title : Decoupling Cores, Kernels, and Operating Systems Author : Gerd Zellweger, Simon Gerber, Kornilios Kourtis, and Timothy Roscoe, ETH Zürich   Abstract We present Barrelfish/DC, an extension to the Barrelfish OS which decouples physical cores from a native OS kernel, and furthermore the kernel itself from the rest of the OS and application state. In Barrelfish/DC, native kernel code on any core can be quickly replaced, kernel state moved between cores, and cores added and removed from the system transparently to applications and OS processes, which continue to execute. Barrelfish/DC is a multikernel with two novel ideas: the use of boot drivers to abstract cores as regular devices, and a partitioned capability system for memory management which externalizes core-local kernel state. We show by ... Continue reading →

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I am a Smartphone and I can tell my user’s walking direction

by Jorge Frisancho on 2015-08-11 09:45:59

Date : 2015. 08. 11 (Tue) 10:00 A.M. Locate : EB5. 533 Presenter : Jorge Frisancho Seminar title: I am a Smartphone and I can tell my user’s walking direction Authors: Authors: Nirupam Roy, He Wang, Romit Roy Choudhury Abstract This paper describes WalkCompass, a system that exploits smartphone sensors to estimate the direction in which a user is walking. We find that several smartphone localization systems in the recent past, including our own, make a simplifying assumption that the user’s walking direction is known. In trying to relax this assumption, we were not able to find a generic solution from past work. While intuition suggests that the walking direction should be detectable through the accelerometer, in reality this direction gets blended into various other motion patterns during the act of walking, including up and down bounce, side-to-side sway, swing of arms or legs, etc. Moreover, the walking direction is in the phone’s local coordinate ... Continue reading →

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Starfish: Efficient Concurrency Support for Computer Vision Applications

by Jinyoung Choi on 2015-08-03 15:37:15

* 동영상 강의로 진행됩니다.   Date : 2015. 08. 03. (Tue) 10:30 A.M. Locate : EB5. 533   Title : Starfish: Efficient Concurrency Support for Computer Vision Applications Author : Robert LiKamWa and Lin Zhong   Abstract Emerging wearable devices promise a multitude of computer vision-based applications that serve users without active engagement. However, vision algorithms are known to be resource-hungry; and modern mobile systems do not support concurrent application use of the camera. Toward supporting efficient concurrency of vision applications, we report Starfish, a split-process execution system that supports concurrent vision applications by allowing them to share computation and memory objects in a secure and efficient manner. Starfish splits the vision library from an application into a separate process, called the Core, which centrally serves all vision applications. The Core shares library call results among applications, eliminating redundant ... Continue reading →

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Ultrasonic Time Synchronization and Ranging on Smartphones

by Jinse Kwon on 2015-07-27 11:38:51

Date : 2015. 07. 28 (Tue) 10:30 A.M. Locate : EB5. 533 Presenter : Jinse Kwon   Title : Ultrasonic Time Synchronization and Ranging on Smartphones Author : Patrick Lazik   Abstract   In this paper, we present the design and evaluation of a platform that can be used for time synchronization and indoor positioning of mobile devices. The platform uses the Time-Difference-Of-Arrival (TDOA) of multiple ultrasonic chirps broadcast from a network of beacons placed throughout the environment to find an initial location as well as synchronize a receiver’s clock with the infrastructure. These chirps encode identification data and ranging information that can be used to compute the receiver’s location. Once the clocks have been synchronized, the system can continue performing localization directly using Time-of-Flight (TOF) ranging as opposed to TDOA. This provides similar ... Continue reading →

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Reducing Energy Consumption of Alarm-induced Wake-ups on Android Smartphones HotMobile'15

by Jemin Lee on 2015-06-28 17:36:35

Date: 2015. 07. 03. (Fri) 10:00 A.M. Locate: EB5. 533 Presenter: jemin lee Seminar title: Reducing Energy Consumption of Alarm-induced Wake-ups on Android Smartphones HotMobile'15 Authors: Sewook Park, Dongwon Kim, Hojung Cha Abstract: Alarms are often used to set smartphones to perform tasks at scheduled times. Many applications use alarm functionality, and devices consequently experience frequent wake-ups and waste energy. In this paper, we analyze alarm-induced wake-ups in the Android platforms in terms of energy consumption. We propose a “Time Critical Alarm”, in which alarms necessarily accompany wake-ups. We then propose, AlarmScope, a scheme to reduce non-critical alarms and thus minimize energy waste. Our evaluation of widely-used applications on Android smartphones shows that the proposed scheme would save between 2.6% and 12.5% of energy use. paper download Continue reading →

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Duet: Exploring Joint Interactions on a Smart Phone and a Smart Watch

by Jinyoung Choi on 2015-05-18 10:26:14

Date : 2015.05.22.(Fri) 10:00 A.M. Locate : EB5.533 Presenter : Jinyoung Choi   Title : Duet: Exploring Joint Interactions on a Smart Phone and a Smart Watch Author : Xiang ‘Anthony’ Chen, Tovi Grossman, Daniel Wigdor, George Fitzmaurice   Abstract The emergence of smart devices (e.g., smart watches and smart eyewear) is redefining mobile interaction from the solo performance of a smart phone, to a symphony of multiple devices. In this paper, we present Duet – an interactive system that explores a design space of interactions between a smart phone and a smart watch. Based on the devices’ spatial configurations, Duet coordinates their motion and touch input, and extends their visual and tactile output to one another. This transforms the watch into an active element that enhances a wide range of phone-based interactive tasks, and enables a new class of multi-device gestures and sensing techniques. A technical evaluation ... Continue reading →

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The Missing Numerator: Toward a Value Measure for Smartphone Apps

by Jemin Lee on 2015-04-08 10:36:23

Date: 2015. 04. 08. (Fri) 10:00 A.M. Locate: EB5. 533 Presenter: Jemin Lee Seminar title: The Missing Numerator: Toward a Value Measure for Smartphone Apps Authors: Anudipa Maiti and Geoffrey Challen Abstract: While great strides have been made in measuring energy consumption, these measures alone are not sufficient to enable effective energy management on battery-constrained mobile devices. What is urgently needed is a way to put energy consumption into context by measuring the value delivered by mobile apps. While difficult to compute, an accurate value measure would enable cross-app comparison, app improvement, energy inefficient app detection, and effective runtime energy allocation and prioritization. Our paper motivates the problem, describes requirements for a value measure, discusses and evaluates several possible inputs to such a measure, and presents results from a preliminary (unsuccessful) attempt to formulate one.  Download: paper   Continue reading →

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A case for battery charging-aware power management and deferrable task scheduling in smartphones

by Donggeon Han on 2015-04-03 09:56:17

Date: 2015. 04. 03. (Fri) 10:00 A.M. Locate: EB5. 533 Presenter: Donggeon Han Seminar title: A case for battery charging-aware power management and deferrable task scheduling in smartphones Authors: Salma Elmalaki Abstract: Prior battery-aware systems research has focused on discharge power management in order to maximize the usable battery lifetime of a device. In order to achieve the vision of perpetual mobile device operation, we propose that software also needs to carefully consider the process of battery charging. This is because the power consumed by the system when plugged in can influence the rate of battery charging, and hence, the availability of the system to the user. We characterize the charging process of a Nexus 4 smartphone and analyze the charging behaviors of anonymous Nexus 4 users using the Device Analyzer dataset. We find that there is potential for software schedulers to increase ... Continue reading →

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Contextual Experience Sampling of Mobile Application Micro-Usage

by Jinyoung Choi on 2015-03-16 16:06:33

Date : 2015. 03. 20. (Fri) 10:00 A.M. Locate : EB5. 533 Presenter : Jinyoung Choi   Seminar title: Contextual Experience Sampling of Mobile Application Micro-Usage Authors Denzil Ferreira, Jorge Goncalves, Vassilis Kostakos, Louise Barkhuus, Anind Dey Abstract Research suggests smartphone users face “application overload”, but literature lacks an in-depth investigation of how users manage their time on smartphones. In a 3-week study we collected smartphone application usage patterns from 21 participants to study how they manage their time interacting with the device. We identified events we term application micro-usage: brief bursts of interaction with applications. While this practice has been reported before, it has not been investigated in terms of the context in which it occurs (e.g., location, time, trigger and social context). In a 2-week follow-up study with 15 participants, we captured participants’ context while micro-using, with a ... Continue reading →

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User interaction-based profiling system for Android application tuning

by Jorge Frisancho on 2015-01-27 04:12:26

Date : 2015. 01. 27 (Tue) 01:00 P.M. Locate : EB5. 533 Presenter : Jorge Frisancho Seminar title: User interaction-based profiling system for Android application tuning Authors: Seokjun Lee, Chanmin Yoon, Hojung Cha Abstract Quality improvement in mobile applications should be based on the consideration of several factors, such as users' diversity in spatio-temporal usage, as well as the device's resource usage, including battery life. Although application tuning should consider this practical issue, it is difficult to ensure the success of this process during the development stage due to the lack of information about application usage. This paper proposes a user interaction-based profiling system to overcome the limitations of development-level application debugging. In our system, the analysis of both device behavior and energy consumption is possible with fine-grained process-level application monitoring. By providing fine-grained information, including user ... Continue reading →

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BatteryExtender: An Adaptive User-Guided Tool for Power Management of Mobile Devices

by Jemin Lee on 2015-01-19 21:46:21

Date : 2015. 01. 20 (Tue) 01:00 P.M. Locate : EB5. 533 Presenter : Jemin Lee   Title: BatteryExtender: An Adaptive User-Guided Tool for Power Management of Mobile Devices Authors     Grace Metri   Department of Computer Science, Wayne State University Abstract The battery life of mobile devices is one of their most important resources. Much of the literature focuses on accurately profiling the power consumption of device components or enabling application developers to develop energy-efficient applications through fine-grained power profiling. However, there is a lack of tools to enable users to extend battery life on demand. What can users do if they need their device to last for a specific duration in order to perform a specific task? To this extent, we developed BatteryExtender, a user-guided power management tool that enables the reconfiguration of the device’s resources based on ... Continue reading →

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VIT: A Timer Hypercall to Support Real-time of Guest Operating Systems

by Guest on 2015-01-13 12:35:56

Abstract Guest operating systems running over the virtual machines share a variety of resources. Since CPU is allocated in a time division manner it consequently leads them to having the unknown physical time. It is not regarded as a serious problem in the server virtualization fields. However, it becomes critical in embedded systems because it prevents guest OS from executing real time tasks when it does not occupy CPU. In this paper we propose a hypercall to register a timer service to notify the timer request related real time. It enables hypervisor to schedule a virtual machine which has real time tasks to execute, and allows guest OS to take CPU on time to support real time. The following experiment shows its implementation on Xen-Arm and para-virtualized Linux. We also analyze the real time performance with response time of test application and frames per second of Mplayer. Continue reading →

463 Views

powerlet:An active battery interface for smartphones

by Donggeon Han on 2015-01-13 12:34:14

Date : 2015. 01. 13 (Tue) 13:00  Locate : EB5. 533 Presenter : Donggeon Han   Title : Powerlet: An Active Battery Interface for Smartphones Authors Wonwoo Jung, Yohan Chon, Dongwon Kim, Hojung Cha (Department of Computer Science, Yonsei university, Seoul, Korea) Abstract A smartphone battery interface should provide ener-gy-related information efficiently with high accuracy be-cause it is the basis for user actions on battery consumption. Previous studies have mainly focused on battery information per se, but the effectiveness of user interaction with the interface has barely been studied. In this paper, we first discuss the results of a survey on different types of ener-gy-related information and features to investigate what users want in terms of battery consumption for smartphones. We then introduce Powerlet, which is a new battery interface that attempts to actively interact with users to provide battery usage information. We validated the efficiency of ... Continue reading →

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