Judul: Pengaruh Perubahan Tutupan Lahan dan Pemanfaatan Sumberdaya Air terhadap Kualitas Air Sungai di Daerah Aliran Sungai Cisadane Segmen Hulu
Abstrak: Increasing the number of residents in the Cisadane watershed area upstream segment cause high river water use and land cover changes. This negative impact on the incidence of pollution load and the source of pollutants/waste that may affect the water quality of rivers and indirectly affect the level of river water pollution. The water quality is very depend on the effort to meet the needs of water for each utility. Therefore, research on the effects of land cover change and water resources utilization of river water quality in the Cisadane watershed upstream segment needs to be done. This research was conducted in the Cisadane watershed area upstream from June to August 2009. Equipments used, such as water quality data, land cover, population, utilization of river water, debit, and livestock. The instrument used is a Arcview 3.2 program and MINITAB release 14. Data processing is done by analysis of land cover change, analysis of changes in water quality, pollution load, pollution load carrying capacity, the analysis of public understanding, and study the influence of land cover changes on water quality. During the period 2005-2008 land cover changes in the Cisadane watershed area upstream shown by the decrease of forest area (72.88%), shrubs (88.18%), open land (91.14%), and the fields ( 97.52%), and increasing plantation area (102.46%), and residential (34.21%).Utilization of river water in the Cisadane watershed area upstream was quite high. For 93% of the 190 families interviewed using Cisadane River for MCK. Pollutant sources that can be seen is garbage (16%) and wastewater (30%). The dominant pollution load comes from domestic waste (4067.86 tons/month 4129.80 BOD and TSS) and livestock waste (3.24 tons/month of BOD and 17.05 tons/month TSS). This pollution load exceeds the capacity for BOD pollution load of each month and it ranged from 2484 tons/month to 3801 tons/month, while for TSS pollution load capacity not exceeding pollution load for each month. Changes in land cover and use of river water affects river water quality. This can be demonstrated by increasing in TDS (18 mg/l), BOD (20.8 mg/l), phosphate (0.303 mg/l), and COD (38 mg/l) which tends to exceed water quality standards. If viewed based on key parameters of water quality (BOD, COD, TSS), the correlation of test results on the α level 0.1 also could be concluded that there is a relationship between changes of land cover with water quality, although the significance level is relatively small. The icreasing of water quality parameters caused the decrease of Water Quality Index from 85,58 to 73,66, but the condition of the waters is still relatively moderate to good.
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Judul: Water Quality of the Downstream Cisadane River and Its Feasibility as a Source of Clean Water and Dringking Water for Residential Areas
Abstrak: Sungai Cisadane memiliki fungsi dan nilai yang sangat tinggi bagi kehidupan manusia. Namun, kegiatan manusia di DAS Cisadane dan di Sungai Cisadane dapat mengancam fungsi dan pemanfaatan perairan karena dapat menurunkan kualitas air Sungai Cisadane. Penelitian ini bertujuan untuk menentukan kelayakan kualitas air Sungai Cisadane untuk air baku air minum terkait dengan dinamika akibat pasang-surut dan musim. Pemantauan di lakukan selama tahun 2020 di Sungai Cisadane bagian hilir. Parameter kualitas air yang diamati meliputi TSS, warna, kekeruhan, bau, BOD, COD, amonia, nitrat, nitrit, fosfat, total P, sulfida, Zn, Fe, As, Pb, Cd, Cu, Hg, Se, Cr6+, Mn, sianida, deterjen, dan Total Coliform. Analisis dilakukan secara deskriptif, dan dengan penentuan Indeks Pencemaran (IP). Hasil analisis menunjukan bahwa kondisi musim, musim hujan dan musim kemarau, dan kondisi ketinggian muka air yang dipengaruhi oleh pasang surut laut berpengaruh pada beberapa parameter kualitas air. Kecuali NO3, PO4, H2S, Ar, Cd, Se, Cr6+, sianida dan deterjen. Berdasarkan Indeks Pencemaran (IP) perairan bagian hilir S. Cisadane telah tercemar ringan sampai berat, sehingga air tidak dapat digunakan sebagai sumber baku air minum tanpa melalui pengolahan terlebih dahulu., The Cisadane River has a very high function and value for human life. However, human activities in the Cisadane watershed and in the Cisadane River can threaten the function and utilization of the waters because they can reduce the water quality of the Cisadane River. This study aims to determine the appropriateness of the water quality of the Cisadane River for drinking water related to the dynamics due to tides and seasons. Monitoring was carried out during 2020 in the lower reaches of the Cisadane River. Water quality parameters observed included TSS, color, turbidity, odor, BOD, COD, ammonia, nitrate, nitrite, phosphate, total P, sulfide, Zn, Fe, As, Pb, Cd, Cu, Hg, Se, Cr6+, Mn , cyanide, detergent, and Total Coliform. The analysis was carried out descriptively, and by determining the Pollution Index (IP). The results of the analysis show that seasonal conditions, rainy and dry seasons, and water level conditions which are affected by sea tides affect several water quality parameters. Except NO3, PO4, H2S, Ar, Cd, Se, Cr6+, cyanide and detergents. Based on the Pollution Index (IP) the downstream waters of Cisadane river have been lightly to heavily polluted, so that the water cannot be used as a raw source of drinking water without going through treatment first.
Keyword: Pollution index, seasons, tides, water quality

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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