Judul: Model of water pollution control on Surabaya River Region
Abstrak: The Surabaya River plays an important role as water supply of the Surabaya PDAM, irrigation, industry, transportation, and means of recreation. However, domestic, industrial, and agricultural waste that were discharged into the river stream polluted the Surabaya River and decreased the carrying capacity and assimilative capacity. Therefore, effort to monitor and control the Surabaya River water pollution need to be well organized and implemented. The aim of the research is to develop a model of water pollution control on Surabaya River region. The research was conducted in five steps, i.e. (1) determine the existing condition of physical and chemical parameters, (2) determine the load pollution and level of pollution, (3) determine the priority of reduction activities of loading pollution and technology control, (4) build dynamics model of water pollution control, and (5) formulate policies or scenarios of water pollution control of the Surabaya River. The research was carried out based on field survey, in situ and laboratory sample examination, questionnaire, and expert judgement. The loading pollution was determined by rapid assessment. The STORET method and pollution index were used to determine the water quality status and level of water pollution. Analytical hierarchy process (AHP) and comparative performance index (CPI) were used to determine the priority of reduction activities and technology control. Pollution control model developed in this study was built into three sub-models, namely: (1) ecology sub-model, (2) social sub-model, and (3) economy sub-model using powersim constructor 2.5 version. Pollution control scenarios were developed using prospective analysis. The results of water pollution parameters such as total suspended solid (TSS), dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrite (N-NO2 Keywords: pollution control, prospective analysis, surabaya river, system approach ), and the level of mercury (Hg) were higher than the allowable class 1 standard. The sources of Surabaya River pollution mainly are domestic and industrial waste with total load of BOD, COD, and TSS are 55.49, 132.58, and 210.13 ton/day, respectively. According to water quality status, the Surabaya River is categorized as heavy polluted and the loading pollution need to be decreased. Simple management and efficiency are mainly criteria for reduction activities of loading pollution with determining water class as top alternative following with illumination and calculated the carrying capacity toward water pollution load. The wastewater garden, filtration, screening, and biofilter are priority of technology control in sequence. By using prospective analysis, there were five important factors that affect the future of the Surabaya River water pollution control, i.e.: (1) population growth and community awareness, (2) community perception, (3) implementation of regulations, (4) commitment/local government support, and (5) system and institutional capacity. There are three development scenarios, that are pessimistic, moderate and optimistic. The moderate and optimistic scenario are the realistic scenarios that occur in the future for Surabaya River water pollution control in considering of ecology, social and economy aspects.
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Judul: Model of integrated management sustainable at youtefa bay
Abstrak: The Youtefa Bay is one of the important resources. The water in this place is used for fishery, transportation, and ecotourisme. Youtefa Bay is located at the west of Jayapura city. Youtefa Bay is surrounded by settlement where most of resident are fisherman and farmers. The aim of this research is to develop a model of Youtefa Bay. The research was conducted in five steps, i.e. (1) to determine the existing condition of physical and chemical parameters, (2) to determine the level pollution, load pollution, and assimilative capacity, (3) to determine of water pollution control strategy, (4) to develop model of management institution, (5) to develop model management Youtefa Bay a similar prominent purpose. The research was carried out based on field survey, in situ and laboratory sample examination, questionnaire, and expert judgement. The STORET method and pollution index were used to determine the water quality status and level of water pollution. The pollution loading was determined by rapid assessment. Youtefa Bay institution determine Interpretative Structural Modelling (ISM). Pollution control by means of descriptive. Management model develop in this study was built into three sub-models, namely (1) pollution source sub-model, (2) The loading pollution sub-model, and (3) water quality sub-model using program powersim studio expert 2005 version. The results of water pollution parameters such as total suspended solid (TSS), dissolved oxygen (DO), Nitrate (NO3), fosfate (PO4), were higher than the allowableness water sea for sea biota standard. Acording to water quality status, the Youtefa Bay is categorized as of light, medium, and heavy. Assimilation capacities are BOD 27 ton/month, TSS 2354 ton/month, NH3 54 ton/month, COD 286 ton/month, NO3 9087 ton/month, and PO4 12 ton/month. The Youtefa Bay water pollution control, i.e (1) institution approach, (2) law approach implementation, (3) social approximation, (4) approximation economy, (5) space arrangement approximation. The key element management Youtefa Bay is the policy commitment approximation, and relations strengthen inter stakeholder, realization plan approximation, and strategy plan priority. There are three development scenario, that are including optimistic scenario. The optimistic scenario are the realistic scenario that occur in the future for management Youtefa Bay in considering of ecology, social, and economy aspects. The conclusion is the Youtefa Bay polluted light, medium, and heavy, and it’s very important to analiyze the pollution level of the Youtefa Bay periodically in terms of it’s sustainability.
Keyword: Youtefa Bay, Water pollution level, pollution load, assimilation, rapid assessment capacity, pollution control, Interpretative Structural Modeling

Judul: igenvalues and Eigenvectors of Tridiagonal Matrix with Non Constant and Recurrent Diagonal Entries.
Abstrak: Matriks tridiagonal adalah suatu matriks yang mempunyai entri-entri bernilai nol kecuali pada diagonal utama, di bawah diagonal utama (subdiagonal) dan di atas diagonal utama (superdiagonal). Entri pada diagonal utama tidak konstan dan berulang. Setiap entri pada matriks tridiagonal ini adalah bilangan kompleks. Dalam karya ilmiah ini, akan dibuktikan 3 teorema untuk menentukan nilai eigen dengan 2 kasus dan 1 teorema untuk menentukan vektor eigen. Teorema pertama menentukan polinomial karakteristik dari matriks tridiagonal. Polinomial karakteristik dari matriks tridiagonal tersebut digunakan untuk menentukan nilai eigen pada teorema kedua dan ketiga serta menentukan vektor eigen pada teorema keempat
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