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"This study is an attempt to elucidate the patterns and trends of migration and urbanization in Indonesia, with specific reference to the last 50 years. Emphasis will be on the use of measures commonly used in demographic analyses in so far as they are relevant to understanding internal migration in Indonesia. In analyses of fertility and mortality useful measures for demographic analyses have been developed. The extensive use of life tables in studies of mortality estimating procedures in fertility studies indicate that demographic techniques can contribute in overcoming the problem of limited data, so that in the absence of good vital statistics a satisfactory estimate of demographic parameters can be made. The development of model life tables in the last two decades by the Princeton group and the United Nations was a breakthrough in overcoming problems caused by poor population data in many developing countries. This is particularly true for the purpose of estimating mortality and making population projections for a country. The wide use of these life tables, even with all their limitations, turn out to be very useful in elucidating the current? situation as a basis for future projection and important policy guidance. While the most sophisticated techniques in demography have been productively applied in analyze of fertility and mortality (Cho et al 1980), little has been done in the area of migration and urbanization analysis in Indonesia. Some scholars in analyzing migration based on the 1971 Census used limited measures of migration in Indonesia, both provincial and regional migration (Speare, 1975, Sundrum, 1976 and Hugo, 1975 and 1980): An analysis of a similar kind was made by McNicoll using limited data from the 1961 Census and the multiple rounds of the Socio Economic Surveys (Susenas) conducted by the Central Bureau of Statistics beginning in the early 1960s. In the area of urbanization, even fewer studies have utilized the available techniques in demography, probably with the exception of Hugo {1981). The analysis of migration in this study is based on theories and techniques of demography in order to provide a conceptual framework for understanding the phenomena and from there derive some policy implications and policy recommendations relevant for development. A population redistribution policy according to Pryor (1979) is expressed as follows : "The population redistribution policy of a nation can be viewed as reflecting the changing character and regional horizontal distribution of modernization and development, and the qualitative (vertical) aspects of the institutional and socio cultural milieu". Pryor further? elaborated that direct policies are deliberately created, have explicit intentions, are specific in some detail, are usually linked to both goals and projects, and their relevance and outcomes will be monitored and evaluated. Indirect policies are consequential and subsidiary to other goals, are implicit and non-purposive. It is part of the aim of this study to provide recommendations for a population redistribution policy. The study of migration can take different forms. It can be approached from an economic, demographic, sociological, geographic or other points of view. It can be approached from any combination of disciplines, in other words from an interdisciplinary perspective. The first systematic study of migration was one conducted by Ravenstein (1885, 1889). His paper presented in March 1885 be-fore the Royal Statistical Society in England and later published in the "Journal of Royal Statistical Society" in 1885, was called the "Laws of Migration". The paper based on the analysis of the 1881 British Census was criticized for not being empirically testable?"

"Studi ekologi mengajarkan adanya hubungan antara suatu spesies dengan lingkungannya secara keseluruhan, dan hubungan saling ketergantungan dari semua bagian bumi dalam hubungan sistemik: lapisan bawah geofisik, atmosfir dan iklim, tanaman dan binatang. Juga ternyata bumi tergantung pada matahari sebagai sumber energinya dan bulan yang berpengaruh terhadap pasang surut air (Campbell 1985:6; 194-195).Untuk menerangkan bagaimana bentuk hubungan saling ketergantungan itu, diambil sebagai unit dasar analisis adalah ekosistem, yang dapat didefinisikan sebagai suatu kawasan alam yang terdiri atas organisme hidup dan unsur-unsur inorganik yang berinteraksi untuk mempertukarkan materi. Sebagai contoh dapat diambil suatu ekosistem hutan atau kolam, dimana diperlihatkan hubungan timbal batik dan adanya ketergantungan satu soma lain antara spesies binatang dan tanaman, demikian juga pada bahan kimia inorganik dalam lingkungan itu (Ibid.:7 mengambil dari Odum 1971).Dalam ekosistem itu terdapat suatu keseimbangan yang dinamakan homeostatic, yaitu kemampuan ekosistem untuk menahan berbagai perubahan dalam sistem secara keseluruhan (Reksasoedarmo, Kartawinata dan Soegiarto 1986:15). Lebih lanjut Odum mengatakan " By steady-state, we mean a self-adjusting equilibrium or balance condition relatively immune to at least small-scale disturbances ("Dengan keadaan seimbang, kita maksudkan suatu ekuilibrium yang menyelaraskan diri atau kondisi seimbang yang relatif tahan paling tidak terhadap goncangan-goncangan berskala kecil") (Odum 1983:4). Odum juga menjelaskan bagaimana setiap unsur dalam ekosistem itu menduduki habitat dan relungnya masingmasing (Campbell 1985:8;14).Sedang ekologi manusia mempelajari adanya hubungan yang erat antara manusia dan lingkungan (termasuk faktor-faktor seperti iklim, tanah), dan pertukaran energi dengan makhluk hidup lainnya, termasuk tanaman, binatang, dan kelompok manusia lainnya (Ibid.:6-7). Dan ekologi budaya mempelajari bagaimana cara kebudayaan suatu kelompok manusia beradaptasi dengan sumberdaya lingkungannya dan terhadap eksistensi dari kelompok manusia lainnya (ibid.:7; Steward 1977:43)."

"ABSTRAKHarmonisa dan dampaknya didalam sistem daya listrik semakin meningkat akibat penggunaan peralatan listrik yang dikendalikan dengan perangkat elektronik dan perangkat lainnya penghasil frekwensi tinggi. Satu hal penting yang diperhatikan didalam mengevaluasi dampak harmonisa adalah efek harmonisa pada komponen sistem daya listrik. Transformator adalah perangkat utama didalam sistem daya listrik. Meningkatnya harmonisa didalam sistem daya menyebabkan kenaikan rugi daya listrik didalam kumparan transformator dan menurunkan kemampuannya dalam membatasi penyebaran aliran harmonisa triplen.Dalam perkembangan teknologi transformator peredam distorsi harmonisa terdapat berbagai tipe konfigurasi hubungan kumparan untuk berbagai kondisi pembebanan diantaranya adalah transformator Vee/vee, T-Scott, Le Blanc, Dy (delta-wye) atau Dz (delta-zigzag). Berdasarkan literatur dan simulasi pembebanan transformator tersebut diketahui bahwa transformator tersebut belum optimal menghambat penyebaran aliran harmonisa triplen ke sisi sumber.Dalam disertasi ini transformator delta primer ? transposisi zigzag sekunder (Dtz) dimodelkan berdasarkan tiga prinsip penghambatan induksi medan elektromagnetik, yaitu prinsip pertama menyeimbangkan induksi fluks magnetik; dan prinsip kedua penghambatan fasa fluks harmonisa; serta prinsip ketiga menyirkulasikan sisa induksi fluks magnetik harmonisa. Transposisi kumparan zigzag dilakukan dengan membagi setiap kumparan fasa sekunder menjadi tiga bagian identik dan meletakkannya pada ketiga kaki yang berbeda. Hal ini bertujuan untuk menyeimbangkan induksi fluks magnetik arus harmonisa triplen dari beban nonlinier satu fasa. Kelebihan tambahan transposisi zigzag dapat memperbesar impedansi dalam rangkaian transformator pada saat band frekwensi harmonisa triplen sehingga magnitude arus harmonisa triplen dapat diturunkan. Dengan semakin sedikitnya arus harmonisa triplen maka induksi ggm (ampere.lilitan) beban didalam kumparan delta primer akan turun. Hasilnya, magnitud arus harmonisa triplen yang bersirkulasi menurun sehingga tidak mendistorsi tegangan dan arus di sisi sumber.Dalam penelitian pada disertasi ini dilakukan simulasi untuk arus arus harmonisa triplen yang dibangkitkan didalam kumparan primer dan sekunder transformator Dtz. Pengujian pembebanan pada sistem tiga fasa dilakukan untuk kondisi beban seimbang maupun beban tidak seimbang. Dari eksperimen dan simulasi dapat ditunjukkan bahwa tingkat distorsi (THD) arus harmonisa didalam kumparan sekunder pada kondisi beban seimbang adalah 70,8%, dan di sisi primer adalah 24,3%. Sedangkan untuk kondisi beban tidak seimbang, tingkat distorsi (THD) didalam kumparan sekunder adalah 68,44% dan di sisi delta primer adalah 26,4%. Hal ini menunjukkan bahwa transformator Dtz memiliki kemampuan filter untuk menurunkan THD arus sebesar 42 ? 46% untuk kondisi beban seimbang dan tidak seimbang, dengan kata lain menghambat arus harmonisa triplen mengalir ke sisi sumber, sehingga sangat cocok untuk diterapkan pada beban beban yang banyak menghasilkan harmonisa triplen terutama di industri.Dengan membandingkan hasil simulasi komputer dengan data pengukuran melalui eksperimen laboratorium, ini dibuktikan bahwa penggunaan transformator Dtz adalah salah satu metode untuk menurunkan arus harmonisa dan menghambat aliran harmonisa ke sisi sumber.

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ABSTRACTHarmonics and their impacts in the electric power system have increased due to the use of electrical equipments which are controlled by the electronic devices and other devices generating high frequency. One of important considerations when evaluating the impact of harmonics is their effects on the power system components and loads. Transformers are the major components in the electrical power systems. The increasing of harmonic level in power systems may cause the increasing of power losses in the transformer winding and in turn will reduce its ability to limit the triplen harmonics current flow to the distribution system.There are various types of harmonic filter-capable transformers for various loading conditions such as Vee/vee, T-Scoot, Le Blanc, Dy (delta-wye) and Dz (delta-zigzag) transformer. Based on review on literature and simulation of transformer loading, it can be concluded that those transformers have limitation on inhibiting the spread of the triplen harmonics current into the source side in the delta winding.In this dissertation, delta primary - transposed zigzag secondary (Dtz) winding transformer is modeled based on the three basic electromagnetic inductions. First balance the magnetic flux induction, followed by suppression the phase of harmonics flux, and circulating the remaining magnetic flux harmonic. Transposition of the zigzag winding is done by dividing equally each secondary winding and laid the three into different legs. This is to balance triplen harmonic magnetic flux from the single phase nonlinear load. The additional advantages of the zigzag transposition can enhance internal impedance of its transformer at its triplen harmonics frequency band so that triplen harmonics current can be reduced. With it reducing triplen harmonic current, mmf load induction (ampere.turn) in delta primary can be reduced. The result is reducing magnitude of triplen harmonic circulation and eliminating distortion in the source.The triplen harmonics currents generated on the primary and secondary winding of D tz transformer are simulated in this research of dissertation. Both balanced and unbalanced loads of the three-phase distribution system are examined. The experiment shows that the total THD current in the secondary winding when balanced loads are applied is about 70.8 %, and in the primary side is 24.3 %. While for unbalanced loads, the average THD in secondary winding is 68.44 % and in delta winding is 26.4 %. It means the Dtz transformer has a filter-ability to reduce about 42 - 46 % THD for both balanced and unbalanced loads. This means suppressing triplen harmonics from flowing to the source and thus suitable to apply it to nonlinear load found in industry.Comparing the computer simulation results and data measurements through experiment in the laboratory, it is proved that the use of the proposed Dtz transformer is one of the methods to reduce harmonic currents and inhibit them to enter to the supply system."