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Assessing Trees Diversity in Jebel Elgarrie Forest Reserve in the Blue Nile State, Sudan
Dafa-Alla Mohamed Dafa-Alla,Ahmed Ibrahim Abuelbasher,Haytham Hashim Gibreel,Yousif Elnour Yagoub,Ahmed Ali Hassabelkreem Siddig,Ahmed Mustafa Morad Hasoba 강원대학교 산림과학연구소 2022 Journal of Forest Science Vol.38 No.3
The study aims to examine population indices of mature trees in Jebel Elgarrie forest, Blue Nile State, Sudan. We used remote sensing techniques to stratify the forest into vegetation classes depending on tree density. We distributed 97 circular sample plots (0.1 ha) proportionally to the area of the vegetation classes. In each sample plot we identified, counted and recorded all mature trees (DBH ≥10 cm). We calculated frequency, density, abundance, richness, evenness and diversity for each species and we drew abundance rank curve of mature trees. We used One-Way ANOVA to test for differences (=0.05) in mean density (No./ha) of mature trees between vegetation classes. Results revealed that the forest was conveniently sub-divided into high density (C1), medium density (C2), low density (C3) and bare farm land (C4) classes. We identified fifteen tree species that belong to 10 families and 14 genera. Combretaceae and Fabaceae were the common families while Anogeissus leiocarpa was the most frequently occurring species. While species diversity varied between vegetation classes, diversity of the forest as a whole is low. While mean density of mature trees in C1, C2, C3 and C4 it was 100, 74, 10, and 0, respectively, it was 54 for the whole forest indicating low stocking, Following One-Way ANOVA, multiple comparisons revealed significant differences in mean density of mature trees between C1 & C3 and C2 & C3. The study provided empirical results on population indices of mature tree species, which would be of importance for successful management and conservation of the forest.
IMTAR: Incremental Mining of General Temporal Association Rules
Dafa-Alla, Anour F.A.,Shon, Ho-Sun,Saeed, Khalid E.K.,Piao, Minghao,Yun, Un-Il,Cheoi, Kyung-Joo,Ryu, Keun-Ho Korea Information Processing Society 2010 Journal of information processing systems Vol.6 No.2
Nowadays due to the rapid advances in the field of information systems, transactional databases are being updated regularly and/or periodically. The knowledge discovered from these databases has to be maintained, and an incremental updating technique needs to be developed for maintaining the discovered association rules from these databases. The concept of Temporal Association Rules has been introduced to solve the problem of handling time series by including time expressions into association rules. In this paper we introduce a novel algorithm for Incremental Mining of General Temporal Association Rules (IMTAR) using an extended TFP-tree. The main benefits introduced by our algorithm are that it offers significant advantages in terms of storage and running time and it can handle the problem of mining general temporal association rules in incremental databases by building TFP-trees incrementally. It can be utilized and applied to real life application domains. We demonstrate our algorithm and its advantages in this paper.
Dafa-Alla M.D.,Nawal K.N. Al-Amin 강원대학교 산림과학연구소 2016 Journal of Forest Science Vol.32 No.2
The research was conducted windward of an irrigated Acacia amplicips Maslin windbreak established to protect As Salam Cement Plant from winds and moving sands. Two belts with approximate optical porosities of 50% and 20% were studied in River Nile State, Sudan. The research aimed at assessing the efficiency of the two belts in wind speed reduction and sand deposition. Research methods included: (i) estimation of optical porosity, (ii) measurements of windward wind speeds at a control and at distances of 0.5 h (h stands for windbreak height), 1 h and 2 h at two vertical levels of 0.25 h and 0.5 h, (iii) estimation of relative wind speeds at the three positions (distance and height) at windward and (iv) estimation of wind erosive forces and prediction of zones of sand deposition. Results show that while the two belts reduced windward wind speeds at the two levels for the three distances, belt II was more effective. Nearest sand deposition occurred at 2 h and 1h windward of belt II and belt I, respectively, at level 0.25 h. At level 0.5 h, sand was deposited only at 2 h windward of belt II and no sand deposition occurred windward of belt I. The study concludes that less porous windbreaks are more effective in reducing wind speed and in depositing sand in windward direction at a distance of not less than twice the belt height.
Abuelbashar, Ahmed Ibrahim,Ahmed, Dafa-Alla Mohamed Dafa-Alla,Siddig, Ahmed Ali Hassabelkreem,Yagoub, Yousif Elnour,Gibreel, Haithum Hashim Institute of Forest Science 2022 Journal of Forest Science Vol.38 No.2
The study aims to assess composition, diversity and population indices of natural regeneration of woody species in Jebel El Gerrie forest reserve, Blue Nile State, Sudan. We conducted field work between December 2018 and January 2019. We used random sampling to collect vegetation data in the forest where we made a total of 90 circular sample plots (radius 17.84 m) and distributed them proportionally to the area of each of the four density-based vegetation classes of the forest i.e. high density (C1), medium density (C2), low density (C3) and crop land (C4). In each sample plot we identified all regenerating tree species and counted their regeneration frequencies. We calculated ecological metrics of regeneration frequency, density, abundance, richness, evenness, diversity and importance value index (IVI) and drew abundance rank curve. Results revealed that out of fifteen mature tree species present, natural regeneration of 8 species, which belong to 6 families, was observed. The relatively most frequently naturally regenerating and abundant species were Anogeissus leiocarpa and Combretum hartmannianum. Richness, evenness and diversity of regenerating species were 1.33, 0.82 and 1.7, respectively. One-way ANOVA (α=0.05) of mean regeneration densities disclosed that there were significant differences (F<sub>3,86</sub>=16.77, p=0.000) between C2 & C3 (p=0.000) and C2 & C4 (p=0.000). While regeneration of seven tree species were absent, two, two and four species were of good, poor and fair regeneration status, respectively. A comparison of mean density of natural regeneration with that of parent trees reflects a poor regeneration status of the forest. The study provides empirical results on the regeneration status of species and signifies the need for management interventions for species conservation and restoration, maintenance of biodiversity and sustainable production.
Robust Finite Field Arithmetic for Fault-Tolerant Tate Pairing
손교용,이상혁,Anour F. A. Dafa-Alla 장전수학회 2010 Proceedings of the Jangjeon mathematical society Vol.13 No.1
Protecting against side channel attacks is a very important issue when constructing hardware and software implementations of pairing-based crypto-graphic algorithms. To detect these attacks, in this paper we present a scheme for constructing strong error detection in the Tate pairing which is based upon robust nonlinear systematic error-detecting codes. We also provide not only the explicit formulas for robust ¯eld operations on an arbitrary ¯nite extension ¯eld but also the mathematical analysis behind them.
An analogue to the Erdös-Ko-Rado theorem on q-ary Hamming code
황경원,김태균,Anour F.A. Dafa-Alla 장전수학회 2009 Proceedings of the Jangjeon mathematical society Vol.12 No.2
We prove an anologue to the Erdos-Ko-Rado Theorem on q-ary Hamming code. Let C be a subset of [수식] and all codewords of C have weight k. Let the Hamming distance d(a, b) be in {1,2,...,2Κ} for every a, b in C. If n ≥ 2k - 1, then [수식]