Anarchy in the APSP: Algorithm and Hardness for Incorrect Implementation of Floyd-Warshall

The celebrated Floyd-Warshall algorithm efficiently computes the all-pairs shortest path, and its simplicity made it a staple in computer science classes. Frequently, students discover a variant of this Floyd-Warshall algorithm by mixing up the loop order, ending up with the incorrect APSP matrix. This paper considers a computational problem of computing this incorrect APSP matrix. We will propose efficient algorithms for this problem and prove that this incorrect variant is APSP-complete

Architectural Design of a RISC Processor for Programmable Logic Controllers

this paper, an architecture of the RISC processor for programmabl

Optimization of software development life cycle quality for NPP safety software based on a risk-cost model

As I&C systems in NPPs are being replaced with digital-based systems, the need for cost-effective safety-critical software engineering plans has been received increased attention. This paper proposes a framework for optimizing software development and V&V qualities by incorporating and estimating various risk-cost factors related to SDLC processes. The model determines the optimal software development or V&V quality that gives the minimum value of an objective function which includes three risk-cost factors: 1) software quality control cost; 2) software defect fixing cost; and 3) the cost from NPP accident consequence considering software failure probability. We present a case study using OPR-1000 plant model. The study results showed important SDLC phases where the risk-cost factors can be minimized by achieving high software quality. The proposed method is expected to be useful to software developers and decision makers for assisting NPP software project and quantifying risk from software life cycle on NPP safety

Construction and Commissioning of PAL-XFEL Facility

The construction of Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL), a 0.1-nm hard X-ray free-electron laser (FEL) facility based on a 10-GeV S-band linear accelerator (LINAC), is achieved in Pohang, Korea by the end of 2016. The construction of the 1.11 km-long building was completed by the end of 2014, and the installation of the 10-GeV LINAC and undulators started in January 2015. The installation of the 10-GeV LINAC, together with the undulators and beamlines, was completed by the end of 2015. The commissioning began in April 2016, and the first lasing of the hard X-ray FEL line was achieved on 14 June 2016. The progress of the PAL-XFEL construction and its commission are reported here.11Nsciescopu