| 1. |
- Laukkanen, P., et al.
(författare)
-
Anomalous bismuth-stabilized (2x1) reconstructions on GaAs(100) and InP(100) surfaces
- 2008
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 100, s. 086101-
-
Tidskriftsartikel (refereegranskat)abstract
- First-principles phase diagrams of bismuth-stabilized GaAs- and InP(100) surfaces demonstrate for the first time the presence of anomalous (2 x 1) reconstructions, which disobey the common electron counting principle. Combining these theoretical results with our scanning-tunneling-microscopy and photoemission measurements, we identify novel (2 x 1) surface structures, which are composed of symmetric Bi-Bi and asymmetric mixed Bi-As and Bi-P dimers, and find that they are stabilized by stress relief and pseudogap formation.
|
|
| 2. |
- Punkkinen, M. P. J., et al.
(författare)
-
Bismuth-stabilized (2x1) and (2x4) reconstructions on GaAs(100) surfaces : Combined first-principles, photoemission, and scanning tunneling microscopy study
- 2008
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 78, s. 195304-
-
Tidskriftsartikel (refereegranskat)abstract
- Bismuth adsorbate-stabilized (2x1) and (2x4) reconstructions of the GaAs(100) surfaces have been studied by first-principles calculations, valence-band and core-level photoelectron spectroscopies, and scanning tunneling microscopy. It is demonstrated that large Bi atom size leads to the formation of the pseudogap at the Fermi energy and to the lower energy of an adsorbate-derived surface band, which contributes to the stabilization of the exceptional Bi/GaAs(100)(2x1) reconstruction. It is proposed that the Bi/GaAs(100)(2x4) reconstructions include asymmetric mixed Bi-As dimers, in addition to the Bi-Bi dimers. Based on the calculations, we solve the atomic origins of the surface core-level shifts (SCLSs) of the Bi 5d photoemission spectra from the Bi/GaAs(100)(2x4) surfaces. This allows for resolving the puzzle related to the identification of two SCLS components often found in the measurements of the Bi 5d and Sb 4d core-level emissions of the Bi/III-V and Sb/III-V(100)(2x4) surfaces. Finally, the reason for the absence of the common (2x4)-beta 2 structure and additional support for the stability of the (2x1) structure on the Bi/III-V(100) surfaces are discussed in terms of Bi atom size and subsurface stress.
|
|
| 3. |
- Punkkinen, M. P. J., et al.
(författare)
-
Surface core-level shifts of GaAs(100)(2x4) from first principles
- 2007
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 76:11
-
Tidskriftsartikel (refereegranskat)abstract
- First-principles calculations show that measured surface core-level shifts (SCLSs) of the GaAs(100)(2x4) surfaces can be described within the initial state effects. The calculated As 3d and Ga 3d SCLSs for the beta 2 and alpha 2 reconstructions of the GaAs(100)(2x4) surfaces are in reasonable agreement with recent measurements. In particular, the results confirm that both the lower and the higher binding energy SCLSs, relative to the bulk emission in the As 3d photoelectron spectra, are intrinsic properties of the GaAs(100)(2x4) surfaces. The most positive and most negative As shifts are attributed to the third layer As atoms, which differs from the previous intuitive suggestions. In general, calculations show that significant SCLSs arise from deep layers, and that there are more than two SCLSs. Our previously measured As 3d spectra are fitted afresh using the calculated SCLSs. The intensity ratios of the SCLSs, obtained from the fits, show that as the heating temperature of the GaAs(100)(2x4) surface is increased gradually, the area of the alpha 2 reconstruction increases on the surface, but the beta 2 phase remains within the whole temperature range, in agreement with previous experimental findings. Our results show that the combination of the experimental and theoretical results is a prerequisite for the accurate analysis of the SCLSs of the complex reconstructed surfaces.
|
|
| 4. |
- Cepeda, D., et al.
(författare)
-
CDK-mediated activation of the SCFFBXO28 ubiquitin ligase promotes MYC-driven transcription and tumourigenesis and predicts poor survival in breast cancer
- 2013
-
Ingår i: EMBO Molecular Medicine. - : EMBO. - 1757-4676 .- 1757-4684. ; 5:7, s. 999-1018
-
Tidskriftsartikel (refereegranskat)abstract
- SCF (Skp1/Cul1/F-box) ubiquitin ligases act as master regulators of cellular homeostasis by targeting key proteins for ubiquitylation. Here, we identified a hitherto uncharacterized F-box protein, FBXO28 that controls MYC-dependent transcription by non-proteolytic ubiquitylation. SCFFBXO28 activity and stability are regulated during the cell cycle by CDK1/2-mediated phosphorylation of FBXO28, which is required for its efficient ubiquitylation of MYC and downsteam enhancement of the MYC pathway. Depletion of FBXO28 or overexpression of an F-box mutant unable to support MYC ubiquitylation results in an impairment of MYC-driven transcription, transformation and tumourigenesis. Finally, in human breast cancer, high FBXO28 expression and phosphorylation are strong and independent predictors of poor outcome. In conclusion, our data suggest that SCFFBXO28 plays an important role in transmitting CDK activity to MYC function during the cell cycle, emphasizing the CDK-FBXO28-MYC axis as a potential molecular drug target in MYC-driven cancers, including breast cancer. FBXO28 is identified as part of a SCF complex acting as a regulator of tumor cell proliferation and an important modifier of MYC function. FBXO28 may be a new prognostic factor in breast cancer and a new potential drug target in MYC- driven tumors.
|
|
| 5. |
- Isoaho, J A, et al.
(författare)
-
New course on computational platforms towards nanoscale systems
- 2005
-
Ingår i: 23rd NORCHIP Conference 2005. - : IEEE. - 1424400643 - 9781424400645 ; , s. 226-229
-
Konferensbidrag (refereegranskat)abstract
- In this paper we present an educational approach for a paradigm shift needed when changing from deep submicron CMOS designs to real nano andnanoscaletechnologies [7] in complex communication and computationsystemimplementations. Here we present an introductioncourseimplemented for starting the paradigm shift in curriculum. Here we presentcoursetargets, structure and implementation as well as future designer competence profiles. Thecourseis consisting of five thematic areas: nano-scale technologies, parallelplatforms, concurrent algorithms, reconfigurablesystemsand autonomoussystemmanagement. These thematic areas compound the core of future nanosystems educational program upgrades for current NoC curricula.
|
|
| 6. |
- Rantala, P., et al.
(författare)
-
Novel Agent-Based Management for Fault-Tolerance in Network-on-Chip
- 2007
-
Ingår i: DSD 2007. ; , s. 551-555
-
Konferensbidrag (refereegranskat)abstract
- We introduce a novel agent-based reconfiguring concept for futures Network-on-Chip (NoC) systems. The necessary properties to increase architecture level fault tolerance are introduced. The system control is modeled as multi-level agent hierarchy that is able to increase application fault-tolerance and performance with autonomous reactions of agents. Die agent technology adds a system level intelligence level to the traditional NoC system design. The architecture and functions of this system are described on conceptual level. Communication and reconfigufing data flows are presented as study cases. Principles of reconfiguration of a NoC on faulty environment are demonstrated and simulated. Probability of reconfiguration success is measured with different latency requirements and amount of redundancy by Monte Carlo simulations. The effect of network topology in reconfiguration of a faulty mesh was also under research in the simulations.
|
|
| 7. |
- Wei Yin, A., et al.
(författare)
-
Hierarchical agent monitoring nocs : A design methodology with scalability and variability
- 2008
-
Ingår i: 26th Norchip Conference, Norchip. - 9781424424931 ; , s. 202-207
-
Konferensbidrag (refereegranskat)abstract
- Adopting the bio-inspired system architecture, a hierarchical agent monitoring NoC design method is proposed. Based on circuit conditions traced at the run-time, system settings including resource utilization and power supplies are configured hierarchically and adaptively at each architecture level by corresponding agents. This methodology provides systematic design approaches to VLSI circuits under the influence of unpredictable variations and stringent power constraints. Each level of agents autonomously monitor their local components while being supervised by their higher level counterparts. In this manner, the overall performance and efficiency can be maximized for systems of any scale. The feasibility and innovation of this methodology are explained elaborately with low-power optimization and fault-tolerance services, and architectural alternative analysis on the regular NoC platform is presented. An FFT study case demonstrates the functional effectiveness and flexibility of agent-monitored adaptive system configuration in case of component failures.
|
|
| 8. |
- Yin, A. W., et al.
(författare)
-
Hierarchical Agent Architecture for Scalable NoC Design with Online Monitoring Services
- 2008
-
Ingår i: Proceedings of MICRO 41.
-
Konferensbidrag (refereegranskat)abstract
- Hierarchical Agent Architecture is proposed to provideonline monitoring services to NoC-based systems. Basedon circuit conditions traced at the run-time, system settingsare monitored adaptively by agents at each architectural level.This monitoring approach partitions various online diagnosticand management services onto hierarchical implementation levelsso as to provide scalability and variability for large-scale NoCdesign. This paper explains the monitoring interaction betweenagent levels, and focuses on system optimization alternativeshandled by different agent levels. It further quantitatively analyzesthe feasibility and design alternatives in monitoring communicationinterconnection upon regular tile-based NoC layout.Though still under intensive research, the proposed architectureis endowed with promising potential for highly-integrated NoCdesign.
|
|
| 9. |
- Yin, A. W., et al.
(författare)
-
Hierarchical Agent Based NoC with DVFS Techniques
- 2011
-
Ingår i: International Journal of Design, Analysis and Tools for Integrated Circuits and Systems. - 2223-523X .- 2071-2987. ; 1:1, s. 32-40
-
Tidskriftsartikel (refereegranskat)abstract
- Network-on-Chip (NoC) is a promising architecturein the many-core on-chip systems. A hierarchical agentbased NoC architecture is proposed which enables the NoCto autonomously adjust itself, and provide maximum powerefficiency, fault/variation tolerance and system flexibility. Agentsare software or hardware components which monitor and controlthe system at different granularity. Via the joint efforts andinteractions of agents at all levels of the architecture, systemoptimization can be achieved at the runtime. Agent hierarchy,mapping of agents on regular NoC platforms and the functionpartition among the agents are elaborately discussed.Runtime power management with various Dynamic Voltageand Frequency Scaling (DVFS) techniques is analyzed on thehierarchical agent based NoC platform. Conventional powermonitoring techniques can be flexibly incorporated into the functionsof specific levels of agents. Network condition is observed bythe agents at the runtime, and the power supplies are adjusted atdifferent granularity accordingly. This paper describes the systemarchitectures of two adaptive schemes, with efficient and feasiblealgorithms presented. Quantitative experiments demonstrate thatthey achieve superior power efficiency comparing with the basicarchitecture without any runtime configuration, while different tradeoffs are applied dependent on the monitoring granularity.
|
|
| 10. |
- Yin, A. W., et al.
(författare)
-
Hierarchical agent based NoC with dynamic online services
- 2009
-
Ingår i: ICIEA. ; , s. 434-439
-
Konferensbidrag (refereegranskat)abstract
- As the size of NoCs increases, power consumption and fault/variation tolerance have become two of the most crucial problems for system designers. To address these problems, we propose a NoC architecture based on a hierarchy of monitoring agents. By tracing the circuit properties at run time, the agents at different architectural levels are able to monitor and control over the whole NoC platform. This monitoring approach partitions various online diagnostic and management services onto hierarchical implementation levels so as to provide scalability and variability for large-scale NoC design. This paper explains the monitoring interaction between agent levels, and focuses on system optimization alternatives handled by different agent levels. It further quantitatively analyzes the feasibility and design alternatives in monitoring communication interconnection upon regular tile-based NoC layout.
|
|
