Kyoung-Soo We

HRT-PLRU: A New Paging Schemefor Executing Hard Real-Time Programson NAND Flash Memory

For advanced features of next generation vehicles, the real-time programs in automotive embedded systems are dramatically increasing. For such large volume program codes, this paper proposes a novel framework to use high-density and low-cost nonvolatile memory, i.e., NAND flash memory, as a low-cost means of storing and executing hard real-time programs. Regarding this, one challenge is that NAND flash memory allows only 2 KB page-based read operations not per-byte random accesses, which requires RAM as working storage for code executions. This paper proposes two solutions, i.e., partitioned RAM solution and shared RAM solution, that minimize the RAM size required to deterministically guarantee the deadlines of all the hard real-time tasks. The proposed solutions are verified with the actual real-time programs for unmanned autonomous driving. To the best of our knowledge, this is the first work that allows us to use NAND flash memory for hard real-time program executions with the minimal usage of RAM.

A novel simulation framework for supporting real-time cyber-physical interactions

Simulation methods are widely used when designing complex systems to reduce the development effort and cost. Especially when designing cyber-physical systems (CPSs), the importance of the simulation grows bigger and bigger. To simulate CPSs precisely, a holistic simulator is needed considering cyber and physical systems as a whole. In this paper, we clarify the limitations of the existing simulation techniques and tools when used as CPS simulators: (1) unable to reflect the realtime behavior of the system, (2) do not support interactions with external environments. To overcome these limitations, we specifically propose a two-level simulation architecture and an artificial delay concept. Then, we also address the issues to be considered when the simulator is running on a multi-core system. To apply our proposed technique with concrete application scenarios, we introduce our simulation framework targeting an automotive system simulator.

An efficient and easilly reconfigurable cyber-physical simulator

We propose a new real-time simulation framework for cyber-physical systems (CPSs). It can efficiently dispatch simulation events for real-time simulation of complex events. It can also be easily reconfigured to adapt to various development steps.

WiP Abstract: Cyber Physical Simulations for Supporting Smooth Development from All-Simulated Systems to All-Real Systems

We propose a new simulation scheme for supporting smooth development of cyber-physical systems (CPSs) from all-simulated systems to all-real systems. For this, we introduce two functionalities which cyber physical simulation should provide.

HW Resource Componentizing for Addressing the Mega-complexity of Cyber-physical Systems

Emerging cyber-physical systems (CPSs) demand a new computing abstraction since the traditional ones have fundamental limitations in handling the para-functional also called physical requirements of CPSs such as timeliness, reliability, and evolvability. With the traditional computing abstractions such as processes, virtual memory, etc., multiple software (SW) components share hardware (HW) resources such as CPU and memory in a competitive manner causing unpredictable interferences in the para-functional properties. This problem becomes more serious along with the ever increasing scale and complexity of newly emerging cyber-physical systems. To fundamentally solve this problem, this paper proposes a HW resource componentizing approach that chops the capacity of a HW resource into smaller ones called HW components and dedicates a HW component to each SW component. With the dedicated HW component, each SW component can be guaranteed with the isolated para-functional properties regardless of surrounding SW components. This makes the system-wide issue of validating timeliness, reliability, and evolvability into the per-component validation issue. With this vision, this paper briefly presents a spatial/temporal-division scheduling algorithm that can be generally used for componentizing various HW resources including CPU, network, and RAM.

Using NAND flash memory for executing large volume real-time programs in automotive embedded systems

For advanced features of next generation vehicles, the real-time programs in automotive embedded systems are dramatically increasing. For such large volume program codes, this paper proposes a novel framework to use high-density and low-cost nonvolatile memory, i.e., NAND flash memory, as a low-cost mean of storing and executing hard real-time programs. Regarding this, one challenge is that NAND flash memory allows only 2KB page-based read operations not per-byte random access, which requires RAM as working storage for code executions. In order to minimize the expensive RAM requirements, the proposed framework optimally partitions the RAM for multiple hard real-time tasks and optimally determines the pinning/LRU combination for each RAM partition such that all task deadlines are deterministically guaranteed. The proposed framework is verified with the actual real-time programs for unmanned autonomous driving. To the best of our knowledge, this is the first work that allows us to use NAND flash memory for hard real-time program executions with the minimal usage of RAM.

An Efficient Simulation Technique to Verify Real-time Performance of Vehicle Control Systems

Abstract: When developing a vehicle control system, simulation methods are widely used to validate the whole system in the early development phase. With this regard, the simulator should correctly behave just like the real parts that are not yet implemented while interacting with already implemented parts in real-time. However, most simulators cannot provide functionally and temporally accurate behaviors of the target system. In order to overcome this limitation, this paper proposes a novel real-time simulation technique that can efficiently simulate the temporal behavior as well as the functional behavior of the simulation target system.Keywords: vehicle control system, real-world interaction, simulation correctness, task modeling, timing constraints Copyright© ICROS 2015 I. 서론무인 자율 주행 자동차 등의 자동차 제어 시스템과 같이 크고 복잡한 내장형 컴퓨팅 시스템이 개발될 때 실시간 성능 검증을 위하여 시뮬레이션 기법이 이용된다[1]. 현대 자동차의 경우, 서로 다른 5개의 네트워크에 연결된 70개 이상의 ECU (Electronic Control Unit)를 가지기 때문에 복잡한 구조로 인하여 시뮬레이션을 이용한 검증 없이 한 번에 개발하는 것은 어렵다[2]. 여기에서 언급하는 시뮬레이션이란 대상 컴퓨팅 시스템 및 해당 시스템을 포함하는 네트워크와 네트워크에 연결된 다른 컴퓨팅 시스템 위에서 수행될 일부 혹은 모든 태스크들의 실시간 행태를 PC (Personal Computer) 등의 범용 컴퓨팅 장비에서 모사하는 것을 의미한다. 그러나 시중의 “실시간 시뮬레이션”이라 칭하는 시뮬레이터는 단지 실세계를 모사하기 위한 기능성 검증에 치중할 뿐 타이밍 검증은 전혀 고려되지 않는다. 그렇기 때문에 이미 실제로 개발되어진 시스템과 함께 시뮬레이션 할 때 상호작용이 제대로 이루어지지 않아 정확하지 않은 결

ECU-in-the-Loop Real-Time Simulation Technique for Developing Integrated Vehicle Safety System

Integrated vehicle safety system is a key issue when developing intelligent safety vehicles. In order to validate such complex systems before actual ECU implementation, ECU-in-the-Loop Simulation (EiLS) is widely used. However, current EiLS methods only simulate the functional behavior of the target system thus cannot validate the temporal behavior of the resulting system. Hence, this paper incorporates a real-time simulation technique such that the target systems both functional and temporal correctness can be validated in the early development phase. For the demonstration purpose, we specifically show how our real-time simulation technique aids the development of the integrated vehicle safety system.

Demo abstract: An efficient and easilly reconfigurable cyber-physical simulator

We propose a new real-time simulation framework for cyber-physical systems (CPSs). It can efficiently dispatch simulation events for real-time simulation of complex events. It can also be easily reconfigured to adapt to various development steps.

A Real-Time Simulation Framework for Incremental Development of Cyber-Physical Systems

When developing a CPS, since it is nature of CPS to interact with a physical system, CPS should be verified during its development process by real-time simulation supporting timely interactions between the simulator and existing implemented hardwares. Furthermore, when a part of a simulated system is implemented to real hardwares, i.e., incremental development, the simulator should aware changes of the simulated system and apply it automatically without manual description of the changes for effective development. For this, we suggest a real-time simulation framework including the concept of `port` which abstracts communication details between the tasks, and a scheduling algorithm for guaranteeing `real-time correctness` of the simulator.