Lyapunov functions for nonlinear time-varying systems

For a quite general class of dynamic systems having a single memoryless time-varying nonlinearity in the feedback path some frequency domain stability criteria are developed using Lyapunov's second method. Four classes of nonlinearities are considered, and it is seen that as the behaviour of the nonlinearity is restricted, the stability conditions are relaxed. For the first three classes of non-linearities, the results for time invariant systems are well known, and for two of the classes the result has previously been extended to apply to time-varying situations. The result concerning a significant new class of nonlinearities as well as the extension of the third previously known time-invariant result to cover time-varying systems are original with this paper

Kajian Perubahan Curah Hujan, Suhu dan Tipe Iklim pada Zone Ekosistem di Pulau Lombok

Dampak Perubahan iklim dapat dirasakan secara global. Pulau Lombok merupakan salah satu pulau kecil yang mempunyai tingkat kerentanan terhadap Perubahan iklim lebih besar dibandingkan pulau-pulau besar. Perubahan iklim dapat menyebabkan terganggunya ekosistem yang ada sehingga perlu adanya strategi mitigasi dan adaptasi terhadap Perubahan iklim. Data dan informasi Perubahan iklim merupakan data dasar yang penting untuk merumuskan strategi mitigasi dan adaptasi terhadap Perubahan iklim. Tujuan penelitian ini adalah mendapatkan data dan informasi Perubahan curah hujan, suhu dan tipe iklim serta menelusuri dampaknya terhadap ekosistem hutan di Pulau Lombok. Metode yang digunakan adalah analisis Perubahan iklim (besaran, Perubahan, distribusi spasial dan kecenderungan), dan analisis dampak Perubahan iklim terhadap ekosistem hutan melalui analisis kesenjangan antara data terkini dan data histori. Hasil penelitian menunjukkan bahwa di Pulau Lombok telah terjadi Perubahan iklim yang ditandai oleh Perubahan kecenderungan curah hujan, suhu dan tipe iklim. Dampak Perubahan iklim pada ekosistem hutan antara lain rusaknya ekosistem hutan mangrove, hilangnya jenis-jenis endemik, penurunan tutupan lahan, serta berkurangnya kualitas dan kuantitas mata air

Sistem Perakaran Bidara Laut (Strychnos Lucida R.br.) Untuk Pengendalian Tanah Longsor

One of potential Non Timber Forest Products (NTFPs) in West Nusa Tenggara and Bali is Strychnos lucida R.Br. which is used for medicinal purposes. The species is also potential to use in land rehabilitation of dry land where it offers an additional benefit of landslide control. Part of the plant which has important role in landslide control is root system. Therefore this study aimed to investigate the Strychnos lucida root system in landslide control. The study was held in Bali Barat National Park. Root characteristics observed in the study were the penetration position in the soil, root architecture, and Index of Roots Anchoring (IRA) and Index of Roots Binding (IRB). The result showed that Strychnos lucida root was able to penetrate into deep soil layer and had R-tipe root architecture which can increase shear resistance of soil. Value of IRA and IRB indicated the species had a more vertical roots in every growth stage and a high enough horizontal roots. Based on its root characteristics, Strychnos lucida was able to decrease landslide risk, especially shallow and surface landslide

Broad activation of the ubiquitin-proteasome system by Parkin is critical for mitophagy

Parkin, an E3 ubiquitin ligase implicated in Parkinson's disease, promotes degradation of dysfunctional mitochondria by autophagy. Using proteomic and cellular approaches, we show that upon translocation to mitochondria, Parkin activates the ubiquitin–proteasome system (UPS) for widespread degradation of outer membrane proteins. This is evidenced by an increase in K48-linked polyubiquitin on mitochondria, recruitment of the 26S proteasome and rapid degradation of multiple outer membrane proteins. The degradation of proteins by the UPS occurs independently of the autophagy pathway, and inhibition of the 26S proteasome completely abrogates Parkin-mediated mitophagy in HeLa, SH-SY5Y and mouse cells. Although the mitofusins Mfn1 and Mfn2 are rapid degradation targets of Parkin, we find that degradation of additional targets is essential for mitophagy. These results indicate that remodeling of the mitochondrial outer membrane proteome is important for mitophagy, and reveal a causal link between the UPS and autophagy, the major pathways for degradation of intracellular substrates

Gis Based Flood Hazard and Vulnerability Mapping: a Case Study of Tidal and River Floods in Downstream of Ciasem Watershed, Subang-West Java

Flood events in downstream of Ciasem watershed are believed to occur due to degradation of watershed and mangrove cover. This paper studies the flood hazard and vulnerability caused by tidal and river flood, mainly on vegetation and built up areas as the main element of risk. The observation was focused at downstream of Ciasem watershed, located in MuaraVillage, Blanakan subdistrict, north coastal region of Subang District. Tidal flood hazard was mapped using iteration process in ILWIS 3.4 software while river flood hazard map was made up incorporating elevation, slope and river characteristics using hydrological tools (HEC-geo RAS and HEC-RAS) in ArcGIS 10 software. Those hazard maps were then utilized to determine element of risk covering vegetation and built up areas. Result showed that tidal inundation started to happen in the western area dominated by fish ponds as the main element of risk.When sea level rose up to 90 cm height, settlement areas were experiencing inundation by tidal flood. Ciasem River began to over flowwhen the river discharge exceeded 160 m3/sec and inundated the paddy fields, fish ponds and settlements. This study indicated that fish ponds and paddy fields having high vulnerability to the flood event while that of settlements and roads depend on the construction materials. Flood disaster risk should be reduced by continuing the land rehabilitation activity, restoring mangrove vegetation, implementing government regulations on management and establishment of aquaculture in mangrove, and carefully considering the construction of coastal protection barriers

Tingkat Kerawanan Kebakaran Gambut Di Kabupaten Musi Banyuasin, Sumatera Selatan (Peat Fire Susceptibility in Musi Banyuasin District, South Sumatra)

Forest and land fire in 2015 was a catastrophe in Indonesia, as it did not only cause damage on forest ecosystem and environments, but also impacted human health and economic loss. This research aimed to identify hotspots distribution in 2014-2015 as an indicator of forest and land fire, and to analyze fire susceptibility in Musi Banyuasin district, South Sumatra. Data used for fire prone analysis consisted of land cover map, forest status, hotspots data derived from NOAA18, soil types, topography and moratorium map. Results showed that based on land function, hotspots were mostly found in production forest with hotspots density of 0.049 hotspots km-2. Based on land cover type, hotspots were mostly found in the open land (88 hotspots). Based on soil types, hotspots were mostly occurred on peat soils (180 hotspots and hotspot density 0.048 hotspot km-2). Soil type was mostly associated with hotspot occurrence. Sub-district of Bayung Lencir has the highest fire susceptibility among others. Low precipitation and El-Ninö phenomenon in 2015 were not the only drivers of peat fire. However two main current problems in the Forest Management Unit of Lalan Mangsang Mendis (e.g. illegal logging and open access) were driver factors of peat fire in the district

A Composite Trust Model for Secure Routing in Mobile Ad-Hoc Networks

It is imperative to address the issue of secure routing in mobile ad-hoc networks (MANETs) where the nodes seek for cooperative and trusted behaviour from the peer nodes in the absence of well-established infrastructure and centralized authority. Due to the inherent absence of security considerations in the traditional ad-hoc routing protocols, providing security and reliability in the routing of data packets is a major challenge. This work addresses this issue by proposing a composite trust metric based on the concept of social trust and quality-of-service (QoS) trust. Extended from the ad-hoc on-demand distance vector (AODV) routing protocol, we propose an enhanced trust-based model integrated with an attack-pattern discovery mechanism, which attempts to mitigate the adversaries craving to carry out distinct types of packet-forwarding misbehaviours. We present the detailed mode of operations of three distinct adversary models against which the proposed scheme is evaluated. Simulation results under different network conditions depict that the combination of social and QoS trust components provides significant improvement in packet delivery ratio, routing overhead, and energy consumption compared to an existing trust-based scheme

Mechanical Stretch and PI3K Signaling Link Cell Migration and Proliferation to Coordinate Epithelial Tubule Morphogenesis in the Zebrafish Pronephros

Organ development leads to the emergence of organ function, which in turn can impact developmental processes. Here we show that fluid flow-induced collective epithelial migration during kidney nephron morphogenesis induces cell stretch that in turn signals epithelial proliferation. Increased cell proliferation was dependent on PI3K signaling. Inhibiting epithelial proliferation by blocking PI3K or CDK4/Cyclin D1 activity arrested cell migration prematurely and caused a marked overstretching of the distal nephron tubule. Computational modeling of the involved cell processes predicted major morphological and kinetic outcomes observed experimentally under a variety of conditions. Overall, our findings suggest that kidney development is a recursive process where emerging organ function “feeds back” to the developmental program to influence fundamental cellular events such as cell migration and proliferation, thus defining final organ morphology