Mobile — 71
NSL — 19
NSL Project — 2

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 →


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 →


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 →


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 →


DBT project seminar

by Wonjun Hwang on 2015-07-06 11:17:33

Date: 2015. 07. 10. (Fri) 10:00 A.M. Locate: EB5. 533 Presenter: WonJun Hwang Seminar title: DBT project seminar Continue reading →


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 →


FCRC 2015

by Sihyeong Park on 2015-06-25 15:19:33

Date: 2015. 06. 26. (Fri) 10:00 A.M. Locate: EB5. 533 Presenter: Sihyeong Park Seminar title: FCRC2015   Continue reading →


PALLOC: DRAM bank-aware memory allocator for performance isolation on multicore platforms

by Sihyeong Park on 2015-06-01 17:36:28

Date: 2015. 06. 05. (Fri) 10:00 A.M. Locate: EB5. 533 Presenter: Sihyeong Park Seminar title: PALLOC: DRAM bank-aware memory allocator for performance isolation on multicore platforms Authors: Heechul Yun, Mancuso, R., Zheng-Pei Wu, Pellizzoni, R. Abstract: DRAM consists of multiple resources called banks that can be accessed in parallel and independently maintain state information. In Commercial Off-The-Shelf (COTS) multicore platforms, banks are typically shared among all cores, even though programs running on the cores do not share memory space. In this situation, memory performance is highly unpredictable due to contention in the shared banks. In this paper, we propose PALLOC, a DRAM bank-aware memory allocator which exploits the page-based virtual memory system to allocate memory pages of each application to specific banks. With PALLOC, we can dynamically partition banks to avoid bank sharing among cores, thereby improving isolation on COTS multicore ... Continue reading →


Partitioned Embedded Architecture based on Hypervisor: the XtratuM approach

by Juyeob Kim on 2015-05-27 20:39:01

Abstract—Partitioned sofware architectures were conceived to fulfill security and avionics requirements where predictability is extremely important. Both, the availability of new processors and an increased necessity of security, have opened new possibilities to use efficiently this approach. Avionic industry has consolidated the Integrated Modular Avionics (IMA) as a solution to manage the software growth in functionality and in efficiency. Now, the aerospace sector is adapting these concepts on its developments. One of the solutions used to achieve partitioned systems is based on virtualisation techniques. In this paper we present XtratuM, a bare-metal hypervisor which implements para-virtualization and dedicated device techniques. XtratuM provides a virtual machine that is ’near’ the native one. It permits to execute a set of partitions, containing each one an operating systems and its applications. Security is based on the temporal and spatial isolation ... Continue reading →


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 →


Visualizing Sound

by Jinse Kwon on 2015-05-08 13:15:30

Date : 2015. 05. 15 (Fri) 10:00 A.M. Locate : EB5. 533 Presenter : Jinse Kwon   Title : Visualizing Sound Author : Neil Savage ( science and technology writer based in Lowell, MA. )   Abstract   In the movies, people often discover their room is bugged when they find a tiny microphone attached to a light fixture or the underside of a table. Depending on the plot, they can feed their eavesdroppers false information, or smash the listening device and speak freely. Soon, however, such tricks may not suffice, thanks to efforts to recover speech by processing other types of information.   Researchers in the Computer Science and Artificial Intelligence Laboratory at the Massachusetts Institute of Technology (MIT), for instance, reported at last year's SIGGRAPH meeting on a method to extract sound from video images. Among other tricks, they were able to turn miniscule motions in the leaves of a potted plant into the notes of "Mary Had a ... Continue reading →


Unifying DVFS and Offlining in Mobile Multicores

by Wonjun Hwang on 2015-05-04 18:49:20

Date: 2015. 05. 08. (Fri) 10:00 A.M. Locate: EB5. 533 Presenter: Wonjun Hwang Seminar title: Unifying DVFS and Offlining in Mobile Multicores Authors: Aaron Carroll and Gernot Heiser Abstract: Energy efficiency is a primary design criterion of the modern smartphone due to limitations in battery capacity. Multi-core processors are now commonplace in these devices, which adds a new dimension, the number cores used, to energy management. In this paper we investigate how the mechanisms of frequency scaling and core offlining interact, and how to use them to reduce energy consumption. We find surprising differences in the characteristics of latest-generation smartphones, specifically in the importance of static power. This implies that policies that work well on one processor can lead to poor results on another.  We propose a simple policy that integrates core offlining with frequency scaling and implement it ... Continue reading →


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 →


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 →


A Virtualized Separation Kernel for Mixed Criticality Systems

by Sihyeong Park on 2015-03-24 20:40:36

Date: 2015. 03. 27. (Fri) 10:00 A.M. Locate: EB5. 533 Presenter: SiHyeong Park Seminar title: A Virtualized Separation Kernel for Mixed Criticality Systems Authors: Ye Li, Richard West, Eric Missimer Abstract: Multi- and many-core processors are becoming increasingly popular in embedded systems. Many of these processors now feature hardware virtualization capabilities, such as the ARM Cortex A15, and x86 processors with Intel VT-x or AMD-V support. Hardware virtualization offers opportunities to partition physical resources, including processor cores, memory and I/O devices amongst guest virtual machines. Mixed criticality systems and services can then coexist on the same platform in separate virtual machines. However, traditional virtual machine systems are too expensive because of the costs of trapping into hypervisors to multiplex and manage machine physical resources on behalf of separate guests. For example, hypervisors are needed to schedule separate VMs on physical ... Continue reading →