1,811 research outputs found
An Analysis of a KNN Perturbation Operator: An Application to the Binarization of Continuous Metaheuristics
[EN] The optimization methods and, in particular, metaheuristics must be constantly improved to reduce execution times, improve the results, and thus be able to address broader instances. In particular, addressing combinatorial optimization problems is critical in the areas of operational research and engineering. In this work, a perturbation operator is proposed which uses the k-nearest neighbors technique, and this is studied with the aim of improving the diversification and intensification properties of metaheuristic algorithms in their binary version. Random operators are designed to study the contribution of the perturbation operator. To verify the proposal, large instances of the well-known set covering problem are studied. Box plots, convergence charts, and the Wilcoxon statistical test are used to determine the operator contribution. Furthermore, a comparison is made using metaheuristic techniques that use general binarization mechanisms such as transfer functions or db-scan as binarization methods. The results obtained indicate that the KNN perturbation operator improves significantly the results.The first author was supported by the Grant CONICYT/FONDECYT/INICIACION/11180056.GarcĂa, J.; Astorga, G.; Yepes, V. (2021). An Analysis of a KNN Perturbation Operator: An Application to the Binarization of Continuous Metaheuristics. Mathematics. 9(3):1-20. https://doi.org/10.3390/math9030225S12093Al-Madi, N., Faris, H., & Mirjalili, S. (2019). Binary multi-verse optimization algorithm for global optimization and discrete problems. International Journal of Machine Learning and Cybernetics, 10(12), 3445-3465. doi:10.1007/s13042-019-00931-8GarcĂa, J., Moraga, P., Valenzuela, M., Crawford, B., Soto, R., Pinto, H., … Astorga, G. (2019). A Db-Scan Binarization Algorithm Applied to Matrix Covering Problems. 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PEMANFAATAN MATERIAL BIODEGRADABLE (BESE-ELEMENT) SEBAGAI MEDIA RESTORASI MANGROVE DI PESISIR NEGERI PASSO, KOTA AMBON
Mangrove ecosystems have potential both ecologically, economically, physically, and chemically. The abundance of this potential causes pressure from anthropogenic activities, which results in the degradation of mangrove ecosystems. Several mangrove ecosystems in the Ambon City area have experienced degradation, so restoration is necessary. The Passo State area has the potential for a dense mangrove ecosystem and can be used as a nursery area to support other ecosystems. Increasing the potential of mangrove ecosystems in the Passo State area can be done through restoration using biodegradable materials (BESE-Elements). Mangrove restoration is carried out through community service activities, a collaboration between the Maritime Center and Wardeen Burg Ecology – The Netherlands. The result of the activity is that mangrove ecosystem restoration is carried out in semi-enclosed areas using 10 BESE-Element. Each BESE-Element was planted with 10 mangrove seedlings consisting of 5 seedlings and 5 propagules. The mangrove species planted were Bruguiera gymnorrhiza, Rhizophora apicutala, and Rhizophora stylosa. Around BESE-Elements planted seedlings and mangrove propagules as a control for mangroves in BESE-Elements
Komposisi Jenis Karang Keras (Scleractinia) di Perairan Pantai Utara Pulau Ambon
Terumbu karang merupakan ekosistem pesisir yang secara ekologi paling produktif dengan keanekaragaman tinggi. Penelitian ini bertujuan untuk mengetahui komposisi jenis karang keras (Scleractinia) di perairan pantai utara Pulau Ambon. Pengambilan data dilakukan dengan menggunakan metode sistematik sampling. Data karang yang diperoleh kemudian diidentifikasi, proses identifikasi dilakukan dengan teknik analisa visual menggunakan beberapa referensi Veron (2000), Veron (1986), Suharsono (2017), Coral Finder edisi ketiga, dan Website Corals of The World (http://www.coralsoftheworld.org) untuk melihat jenis-jenis apa saja yang ada pada lokasi penelitian. Hasil penelitian menunjukkan bahwa berdasarkan komposisi taksa jumlah genus terbanyak dari famili Fungidae, jumlah spesies terbanyak dari genus Porites dan jumlah koloni terbanyak dari spesies Porites lutea
Correlation of some water quality parameters and Pb in sediment to gastropod diversity in Ambon Island Waters
The coastal waters of Ambon Island have quite diverse ecosystems that allow for the presence of various organisms, one of which is gastropods. This study aims to analyze the correlation of some water parameters and Pb in sediment to the diversity of gastropods. The research method was carried out by observing the density, water quality parameters, and Pb metal in sediments. Water parameters were measured in situ and analyzed in the laboratory. The distribution of gastropods was analyzed through Principal Component Analysis (PCA). At the same time, the correlation analysis was carried out using the Pearson correlation approach using SPSS v.16. The results showed that the types of gastropods with the highest density in the waters of Ambon Island were Terebralia sulcata, Hebra corticata, and Nerita patula. While the species with the lowest density value were Nassarius olivaceus, Polinices didyma, Lunella cinerea, Conus eburneus, Cypraea isabella, Vexillum plicarium, and Columbella scripta. The Shannon-Wienner Diversity Index ranges from 1.253–2.622, and the diversity index ranges from 0.083-0.207. It was included in the low category caused by the disturbance of water pollution and Pb metal in sediments. Meanwhile, the dominance index ranged from 0.098 to 0.511 indicating species dominance at several observation stations. The waters' physical-chemical parameters strongly correlating with gastropod diversity are DO and Pb, with respective correlation values ​​of r = 0.656 and r = -0.785.  
Portal protein functions akin to a DNA-sensor that couples genome-packaging to icosahedral capsid maturation.
Tailed bacteriophages and herpesviruses assemble infectious particles via an empty precursor capsid (or \u27procapsid\u27) built by multiple copies of coat and scaffolding protein and by one dodecameric portal protein. Genome packaging triggers rearrangement of the coat protein and release of scaffolding protein, resulting in dramatic procapsid lattice expansion. Here, we provide structural evidence that the portal protein of the bacteriophage P22 exists in two distinct dodecameric conformations: an asymmetric assembly in the procapsid (PC-portal) that is competent for high affinity binding to the large terminase packaging protein, and a symmetric ring in the mature virion (MV-portal) that has negligible affinity for the packaging motor. Modelling studies indicate the structure of PC-portal is incompatible with DNA coaxially spooled around the portal vertex, suggesting that newly packaged DNA triggers the switch from PC- to MV-conformation. Thus, we propose the signal for termination of \u27Headful Packaging\u27 is a DNA-dependent symmetrization of portal protein
Monitoraggio topografico e fotogrammetrico della cupola del teatro Massimo
L’articolo riporta i primi risultati di uno studio finalizzato al monitoraggio delle
deformazioni della cupola del Teatro Massimo di Palermo provocate dalle dilatazioni termiche, con
l’impiego di tecniche topografiche e fotogrammetriche integrate. In particolare, sono state utilizzate
due stazioni totali robotizzate e sistemi di fotogrammetria digitale di elevata precisione. Per
correlare gli spostamenti dei carrelli sui quali poggia la struttura in acciaio della cupola con i
gradienti termici, sono state acquisite immagini termiche diversificate. L’obiettivo principale del
lavoro consisteva nel confronto delle due tecniche di rilievo in relazione a misure di deformazione
di entitĂ molto ridotta (sub-millimetrica). I risultati ottenuti dimostrano che i carrelli funzionano
ancora correttamente. Infatti, per un gradiente termico di 6°C misurato dalla termo camera,
entrambe le tecniche topografiche e fotogrammetriche hanno evidenziato spostamenti dell’ordine di
0.8 mm, in accordo con le previsioni del modello deformativo teorico
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