About Operating Systems Lab

We would like to welcome to our Operating Systems Lab. Website! Our Lab. was established in 2007. As the name of our Laboratory indicates, we have an interest in Operating Systems including General Purpose and Embedded Operating Systems. We have published papers in these fields and undertake projects mostly in these fields. The students build up their theoretical and practical training in these fields and gain balanced experiences in Operating Systems.

Please click here to learn more about our research and development projects. Results of Projects are published on famous conferences and journals. Please click here to learn more about our publications.
Thank you for visiting our homepage and feel free to leave a message on our board if you have any comments and suggestions.
If you are interested in working in the Operating Systems Lab. please e-mail Professor Jiman Hong (jiman@ssu.ac.kr)

Research

Embedded Operating Systems

Real-Time Operating Systems

Fault Tolerance Systems

Sensor Networks

Low-Power Systems

Mobile Computing

Embedded Operating Systems

  • An embedded operating system is an operating system for embedded computer systems
  • Embedded operating systems Designed to be very compact and efficient, forsaking many functions that non-embedded computer operating systems provide, and which may not be used by the specialized applications they run.
  • Examples of embedded operating systems coulde include the software used in Automated Teller Machines, Cash Registers, CCTV systems, TV box set, GPS, jukeboxes, etc.
  • The list of Embedded Systems are A/ROSE, BeRTOS, Embedded Linux, MontaVista Software, TynyOS, VxWorks, RTLinux, Windows CE, etc.

Real-Time Operating Systems

  • A real-time operating system (RTOS) is a multitasking opereating system intended for real-time applications. Such applications include embedded systems (programmable thermostats, household appliance controllers), industrial robots, spacecraft, industrial control, and scientific research equipment.
  • A RTOS facilitates the creation of a real-time system, but does not guarantee the final result will be realtime; this requires correct development of the software.
  • A RTOS does not necessarily have high throughput; rather, a RTOS provides facilities which, if used properly, guarantee deadlines can be met generally or deterministically.
  • A RTOS will typically use specialized scheduling algorithms in order to provide the real-time developer with the tools necessary to produce deterministic behavior in the final system.
  • A RTOS is valued more for how quickly and/or predictably it can respond to a particular event than for the amount of work it can perform over a given period of time.
  • Key factors in a RTOS are therefore a minimal interrupt latency and a minimal thread switching latency.
  • An early example of a large-scale real-time operating system was Transaction Processing Facility developed by American Airlines and IBM for the Sabre Airline Reservations System.

Fault Tolerance Systems

  • Fault Tolerance is the property that enables a system(often computer-based) to continue operating properly in the event of the failure of (or one or more faults within) some of its components.
  • If operating system's quality decreases at all, the decrease is proportional to the severity of the failure, as compared to a naively-designed system in which even a small failure can cause total breakdown.
  • Fault Tolerance is particularly sought-after in high-availability or life-critical systems and not just a property of individual machines.
  • Recovery from errors in Fault Tolerance System can be characterised as either roll-forward or roll-back. When the system detects that it has made an error, roll-forward recovery takes the system state at that time and corrects it.
  • Within the scope of an individual system, Fault Tolerance can be achieved by anticipating exceptional conditions and building the system to cope with them, and, in general, aiming for self-stabilization so that the system converges towards an error-free state.

Sensor Networks

  • Consists of spatially distributed autonomous sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants. The development of wireless sensor networks was motivated by military applications such as battlefield surveillance.
  • Area monitoring : In area monitoring, the WSN is deployed over a region where some phenomenon is to be monitored.
  • Environmental monitoring : A number of WSNs have been deployed for environmental monitoring. Many of these have been short lived, often due to the prototype nature of the projects.
  • Windrow Composting : To ensure efficient and effective composting, the temperatures of the windrows must be measured and logged constantly. With accurate temperature measurements, facility managers can determine the optimum time to turn the windrows for quicker compost production.
  • Data visualization : The data gathered from wireless sensor networks is usually saved in the form of numerical data in a central base station. Additionally, the Open Geospatial Consortium (OGC) is specifying standards for interoperability interfaces and metadata encodings that enable real time integration of heterogeneous sensor webs into the Internet, allowing any individual to monitor or control Wireless Sensor Networks through a Web Browser.
  • Information Fusion : In wireless sensor networks has been developed for processing sensor data by filtering, aggregating, and making inferences about the gathered data. Information fusion deals with the combination of multiple sources to obtain improved information: cheaper, greater quality or greater relevance.

Low-Power Systems

  • Dynamic Range : Dynamic range is perhaps the most significant tradeoff in using conventional op amps in a single-supply design.
  • State machine encoding : A number of logic resources are defined by the type of finite state machines implemented.
  • Guarded evaluation : The key to guarded evaluation is to stop inputs from propagating down to additional logic blocks if the resulting outputs do not require updating. Guarding the evaluation of input signals ensures that outputs change values only when it is appropriate.
  • System clock speeds : . System clock frequency has a dramatic impact on the overall power consumption of a board, since clock signals have the highest switching activity and capacitive load. Clock speed directly relates to bandwidth performance

Mobile Computing

  • A generic term describing one's ability to use technology while moving, as opposed to portable computers, which are only practical for use while deployed in a stationary configuration.
  • Insufficient bandwidth : Mobile internet access is generally slower than direct cable connections, using technologies such as GPRS and EDGE, and more recently 3G networks. These networks are usually available within range of commercial cell phone towers. Higher speed wireless LANs are inexpensive, but have very limited range.
  • Security standards : When working mobile one is dependent on public networks, requiring careful use of VPNs.
  • Power consumption : When a power outlet or portable generator is not available, mobile computers must rely entirely on battery power. Combined with the compact size of many mobile devices, this often means unusually expensive batteries must be used to obtain the necessary battery life.
  • Transmission interferences : Weather, terrain, and the range from the nearest signal point can all interfere with signal reception. Reception in tunnels, some buildings, and rural areas is often poor.
  • Potential health hazards : More car accidents are related to drivers who were talking through a mobile device. Cell phones may interfere with sensitive medical devices. There are allegations that cell phone signals may cause health problems.
  • Human interface with device : Screens and keyboards tend to be small, which may make them harder to use. Alternate input methods such as speech or handwriting recognition require training.