Judul: The Effect of Tin Mining on the Diversity of River Fish and Indigenous Knowledge of Local Community in Bangka Island.
Abstrak: Tin mining operation in Bangka significantly damages the aquatic environment, especially the water quality, river fish habitat, and diversity of fish resources. The objective of the research is to analyze the effects of tin mining operations on water quality, fish species diversity, and indigenous knowledge related to the protection and use of river ecosystem. The research was conducted from February to May 2013 in two rivers, the Menduk River - represent river under influenced of tin mining operation - and the Jeruk River represent without tin mining operation. Water quality parameters that measured among others were stream velocity, temperature, brightness, turbidity, TDS (Total Dissolved Solids), TSS (Total Suspended Solids), pH, alkalinity, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD5), and heavy metals (Pb, Zn, Cu, Sn). Fish sampling was carried out by using gill nets with mesh sizes ¾ inch, 1 inch and 1½ inch. Further, a ladle, tangkul and traps are also applied for enriching the fish biodiversity data. Based on water quality data, a Pollution Index (PI) was calculated. Furthermore, a habitat index was analyzed to measure the disturbances of the river habitat. Social aspects are measured through interviews and observations to community leaders and relevant stakeholders. The result shows that, first, the tin mining operations affects is significantly the water quality of the upstream of Menduk River where the mining site are located. The quality of brightness, turbidity and TSS of the upstream river are lower compare to the downstream areas. Furthermore, the water quality along the upstream to downstream of Menduk River is significantly lower than the Jeruk River as shown in the Menduk’s PI that reach 4.2 meanwhile the Jeruk’s PI 1.2. Second, those mentioned habitat changing of the Menduk River, more over affect to the fish diversity. Under disturbed habitat, the fish diversity of Menduk’s river comprise only of 21 species from 10 families. It is different significantly with the relatively undisturbed habitat of Jeruk River where the fish diversity reached 36 species from 16 families. Third, the local community surround both rivers are still maintaining the indigenous knowledge and rules for protecting and sustainable use of rivers and its fish aquatic resource. The elder (dukun) has authority to enforce rules and sanctions and the community members complies the rules. However, since most of the illegal tin mining operated by migrants from outside Bangka Island, the local knowledge, wisdom and local rules are not obey by the migrants.
Keyword: water pollution, freshwater fish biodiversity, tin mining, Indigenous Knowledge, Bangka Island

Judul: Reklamasi lahan pascatambang timah dan tingkat perkembangan wilayah di Kabupaten Bangka
Abstrak: Tin mining industry in Bangka Regency contributes positively to the national income, and increase in Gross Regional Domestic Product (GRDP), labour availability, and economic value. The tin mining also poses negative impacts on the environment. Post-mined reclamation is expected to increase regional economic level and stimulate economic growth so that after the closure of mining activities there is no inequality in the community socio-economic aspect. The aims of the research are: (1) to assess tin post-mined land reclamation techniques for plant growth, (2) to assess the types of reclamation plants suitable to grow and have an economic benefit to the community, (3) to determine priority of the reclamation plant types suitable to grow based on the stakeholders perceptions, (4) to plan an arrangement of plant types and land reclamation techniques in the tin post-mined area, and (5) to determine the level of the community income and regional development in villages with tin mining activities in Bangka Regency. The results show that the reclamation technique that can be implemented was by providing soil ameliorants (manure or compost, top soil and rock phosphate or dolomite) and fertilizers to the tailings, and then provide MAF inoculant or planting cover crops of the leguminoseae familiy and planted with native plants or plants which suitable to grow in the such a tin postmined land conditions. Implementation of the reclamation technique resulted in an increase in land suitability classes to be S3 (marginally suitable) for rubber (Hevea brasiliensis) and S2 (moderately suitable) for sengon (Paraserianthes falcataria) and acacia (Acacia auriculiformis). Based on the stakeholder perception, rubber is the priority plant, while plant which generate economic benefit is sengon. The community income of villages around the tin mining area increased in the period of 2003-2008. At the time of mining activities, hierarchy of some villages around the mine increased but then decreased after the closure of the tin mining activities.
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Judul: Konstruksi aritmetika kurva eliptik F(2m) supersingular dan non-supersingular untuk skema kunci publik ElGamal
Abstrak: Algoritme ElGamal adalah salah satu algoritme kunci publik dengan aritmetik modular p yang mempunyai struktur grip siklik Z(p). Tingkat keanaman algoritme ini terletak pada pemecahan masalah logaritme diskret dari Z(p). Akan tetapi, tingkat keamanan tadi tahun ke tahun semakin menurun yang disebabkan kemampuan pemecahan algoritme diskret semakin meningkat. Untuk memenuhi tingkat keamanan yang memadai dibutuhkan p yang cukup besar yang menyebabkan proses enkripsi dan dekripsi menjadi lambat.
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