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Search Results: 1 - 10 of 22 matches for " Gregorius Parlindungan "
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Indonesia’s VSAT Industry and Role of CSM Today in the Future
Hutahean, Gregorius Parlindungan
Online Journal of Space Communication , 2005,
Abstract: This author discusses the Very Small Aperture Terminal (VSAT) industry in Indonesia, and how CSM (Citra Sari Makmur), is involved in the industry. CSM captures the biggest market share in the VSAT industry Indonesia. The article describes how CSM expands its service from the corporate markets to more public market, such as Internet services and rural telephony.
A Substractive Clustering Based Fuzzy Hybrid Reference Control Design for Transient Response Improvement of PID Controller
Endra Joelianto,Parlindungan H. Sitanggang
ITB Journal of Engineering Science , 2009,
Abstract: The well known PID controller has inherent limitations in fulfilling simultaneously the conflicting control design objectives. Parameters of the tuned PID controller should trade off the requirement of tracking set-point performances, disturbance rejection and stability robustness. Combination of hybrid reference control (HRC) with PID controller results in the transient response performances can be independently achieved without deteriorating the disturbance rejection properties and the stability robustness requirement. This paper proposes a fuzzy based HRC where the membership functions of the fuzzy logic system are obtained by using a substractive clustering technique. The proposed method guarantees the transient response performances satisfaction while preserving the stability robustness of the closed loop system controlled by the PID controller with effective and systematic procedures in designing the fuzzy hybrid reference control system.
Linking Diversity and Differentiation
Hans-Rolf Gregorius
Diversity , 2010, DOI: 10.3390/d2030370
Abstract: Generally speaking, the term differentiation refers to differences between collections for the distribution of specified traits of their members, while diversity deals with (effective) numbers of trait states (types). Counting numbers of types implies discrete traits such as alleles and genotypes in population genetics or species and taxa in ecology. Comparisons between the concepts of differentiation and diversity therefore primarily refer to discrete traits. Diversity is related to differentiation through the idea that the total diversity of a subdivided collection should be composed of the diversity within the subcollections and a complement called “diversity between subcollections”. The idea goes back to the perception that the mixing of differentiated collections increases diversity. Several existing concepts of “diversity between subcollections” are based on this idea. Among them, β-diversity and fixation (inadvertently called differentiation) are the most prominent in ecology and in population genetics, respectively. The pertaining measures are shown to quantify the effect of differentiation in terms of diversity components, though from a dual perspective: the classical perspective of differentiation between collections for their type compositions, and the reverse perspective of differentiation between types for their collection affiliations. A series of measures of diversity-oriented differentiation is presented that consider this dual perspective at two levels of diversity partitioning: the overall type or subcollection diversity and the joint type-subcollection diversity. It turns out that, in contrast with common notions, the measures of fixation (such as FST or GST ) refer to the perspective of type rather than subcollection differentiation. This unexpected observation strongly suggests that the popular interpretations of fixation measures must be reconsidered.
Gregorius Satia Budhi
Jurnal Informatika , 2003,
Abstract: Flexible Manufacturing System (FMS) is a manufacturing system that is formed from several Numerical Controlled Machines combine with material handling system, so that different jobs can be worked by different machines sequences. FMS combine the high productivity and flexibility of Transfer Line and Job Shop manufacturing system. In this reasearch, Activity-Based Costing(ABC) approach was used as the weight to search the operation route in the proper machine, so that the total production cost can be optimized. The search method that was used in this experiment is Simulated Annealling, a variant form Hill Climbing Search method. An ideal operation time to proses a part was used as the annealling schedule. From the empirical test, it could be proved that the use of ABC approach and Simulated Annealing to search the route (routing process) can optimize the Total Production Cost. In the other hand, the use of ideal operation time to process a part as annealing schedule can control the processing time well. Abstract in Bahasa Indonesia : Flexible Manufacturing System (FMS) adalah sistem manufaktur yang tersusun dari mesin-mesin Numerical Control (NC) yang dikombinasi dengan Sistem Penanganan Material, sehingga job-job berbeda dikerjakan oleh mesin-mesin dengan alur yang berlainan. FMS menggabungkan produktifitas dan fleksibilitas yang tinggi dari Sistem Manufaktur Transfer Line dan Job Shop. Pada riset ini pendekatan Activity-Based Costing (ABC) digunakan sebagai bobot / weight dalam pencarian rute operasi pada mesin yang tepat, untuk lebih mengoptimasi biaya produksi secara keseluruhan. Adapun metode Searching yang digunakan adalah Simulated Annealing yang merupakan varian dari metode searching Hill Climbing. Waktu operasi ideal untuk memproses sebuah part digunakan sebagai Annealing Schedulenya. Dari hasil pengujian empiris dapat dibuktikan bahwa penggunaan pendekatan ABC dan Simulated Annealing untuk proses pencarian rute (routing) dapat lebih mengoptimasi total biaya produksi. Sementara itu, dengan digunakannya waktu operasi ideal sebagai Annealing Schedule, waktu proses dapat dimaintain dengan baik. Kata kunci: Flexible Manufacturing Systems, Activity-Based Costing Approach, Simulated Annealing.
Gregorius Satia Budhi
Jurnal Informatika , 2002,
Abstract: The application of Activity Based Costing (ABC) approach to select the set-machine that is used in the production of Flexible Manufacture System (FMS) based on technical and economical criteria can be useful for producers to design FMS by considering the minimum production cost. In the other hand, Heuristic Search is known to have a short searching time. Algorithm Heuristic that using ABC approach as the weight in finding the solution to shorten the equipment selection time during the design / redesign process of the FMS in less than exponential time was designed in this research. The increasing speed is useful because with the faster time in design / redesign process, therefore the flexibility level of part variety that can be processed will become better. Theoretical and empirical analysis in Algorithm Heuristic shows that time searching to get appropriate set of equipment is not too long, so that we can assume that the designed Algorithm Heuristic can be implemented in the real world. By comparing the empirical result of Algorithm Heuristic to the Algorithm Exhaustive, we can also assume that Algorithm Heuristic that using ABC method as the weight for finding solution can optimise the equipment selection problem of FMS based on economical criteria too. Abstract in Bahasa Indonesia : Penggunaan pendekatan Activity Based Costing (ABC) untuk memilih set mesin yang digunakan dalam produksi pada Flexible Manufacture Systems (FMS) berdasar atas kriteria teknis dan ekonomis, dapat membantu pelaku produksi untuk mendisain FMS dengan pertimbangan minimalisasi biaya produksi. Sementara itu, Heuristic Search dikenal memiliki waktu pencarian yang singkat. Pada riset ini didisain sebuah Algoritma Heuristic yang menggunakan pendekatan ABC sebagai bobot dalam pencarian solusi, untuk mempersingkat waktu pemilihan peralatan saat desain/redisain FMS dalam waktu kurang dari waktu Eksponensial. Peningkatan kecepatan ini bermanfaat, karena dengan cepatnya waktu disain / redisain maka derajat fleksibilitas jenis (variety) part yang dapat diproses menjadi lebih baik. Analisis Teoritis dan Empiris pada Algoritma Heuristic menunjukkan bahwa waktu pencarian untuk mendapatkan suatu set peralatan yang tepat adalah cukup singkat, sehingga dapat disimpulkan bahwa Algoritma Heuristic yang didisain dapat diimplementasikan pada dunia nyata. Dengan membandingkan hasil empiris Algoritma Heuristic dengan Algoritma Exhaustive sebagai pembanding, disimpulkan bahwa Algoritma Heuristic yang menggunakan metode ABC sebagai bobot pencarian solusi dapat mengoptimasi problem pemilihan peralatan
Taurocholate Deconjugation and Cholesterol Binding by Indigenous Dadih Lactic Acid Bacteria
HAYATI Journal of Biosciences , 2005,
Abstract: High serum cholesterol levels have been associated with an increased risk for human coronary heart disease. Lowering of serum cholesterol has been suggested to prevent the heart disease. To reduce serum cholesterol levels one may consumed diet supplementat of fermented dairy product such as dadih. Lactic acid bacteria present in dadih may alter serum cholesterol by directly bind to dietary cholesterol and/or deconjugation of bile salts. Acid and bile tolerance, deconjugation of sodium taurocholate, and the cholesterol-binding ability of lactic acid bacteria from dadih were examined. Among ten dadih lactic acid bacteria tested, six strains namely I-11, I-2775, K-5, I-6257, IS-7257, and B-4 could bind cholesterol and deconjugate sodium taurocholate. However, the last four strains were very sensitive to bile. Therefore, Lactobacillus fermentum I-11 and Leuconostoc lactis subsp. lactis I-2775 those were tolerant to acid and oxgall (bile) and deconjugated sodium taurocholate and bound cholesterol could be recommended as probiotic to prevent coronary heart disease.
Gregorius Satia Budhi,Felicia Soedjianto
Jurnal Informatika , 2007,
Abstract: Taking attendance from employees always becomes a problem for Human Resource Department (HRD) in many companies lately. Although there is an automatic check-lock machine, it still has a weakness. This machine can't detect some frauds like the employee swipes double identity card, his card and the others card. Reseachers want to solve this problem by using data mining method, especially market basket analysis.This software will transform the attendance data to compact transaction format by using MaxDiff Histogram method. And it will be processed into frequent itemset with Pincer Search Algoritm. At the final process the employee's association rule will got from frequent itemset. This output will be served to user that is the HRD of a firm.Testing result shows that Data Mining Market Basket Analysis can be used to get pattern of employee's check-lock from a company. And this pattern can help user to detect fraud that is done by employee. Abstract in Bahasa Indonesia : Absensi pegawai selama ini selalu menjadi permasalahan yang pelik bagi bagian HRD di perusahaan - perusahaan yang ada. Walaupun telah ada peralatan absensi otomatis, alat ini masih memiliki kelemahan yaitu, tidak dapat mendeteksi kecurangan pegawai untuk menitipkan kartu absensinya pada karyawan lain untuk diabsenkan. Peneliti berkeinginan untuk mengatasi permasalahan absensi tersebut dengan memanfaatkan metode data mining, khususnya metode market basket analysis, untuk mendeteksi kecurangan ini.Perangkat lunak yang dibuat ini akan mentranformasikan data absensi pegawai menggunakan metode MaxDiff Histogram menjadi format compact transaction yang selanjutnya akan diproses menggunakan Algoritma Pincer Search menjadi frequent itemset. Pada akhirnya dari data frequent itemset ini didapat association rule pegawai untuk disajikan kepada pengguna, yaitu bagian HRD perusahaan.Dari hasil pengujian dapat diketahui bahwa metode Data Mining Market Basket Analysis dapat dimanfaatkan untuk menggali pattern kebiasaan absensi (check-lock) pegawai sebuah perusahaan. Dari sini kemungkinan terjadinya kecurangan saat melakukan absensi masuk / pulang dapat dideteksi. Kata kunci: absensi/check-lock, data mining, MaxDiff histogram, market basket analysis, pincer search
Measuring differentiation among populations at different levels of genetic integration
Elizabeth M Gillet, Hans-Rolf Gregorius
BMC Genetics , 2008, DOI: 10.1186/1471-2156-9-60
Abstract: To fill this gap, a conceptual approach to the description and analysis of patterns of genetic differentiation at arbitrary levels of genetic integration (single or multiple loci, varying degrees of ploidy) is introduced. Measurement of differentiation is based on the measure Δ of genetic distance between populations, which is in turn based on an elementary genic difference between individuals at any given level of genetic integration. It is proven that Δ does not decrease when the level of genetic integration is increased, with equality if the gene associations at the higher level follow the same function in both populations (e.g. equal inbreeding coefficients, no association between loci). The pattern of differentiation is described using the matrix of pairwise genetic distances Δ and the differentiation snail based on the symmetric population differentiation ΔSD. A measure of covariation compares patterns between levels. To show the significance of the observed differentiation among possible gene associations, a special permutation analysis is proposed. Applying this approach to published genetic data on oak, the differentiation is found to increase considerably from lower to higher levels of integration, revealing variation in the forms of gene association among populations.This new approach to the analysis of genetic differentiation among populations demonstrates that the consideration of gene associations within populations adds a new quality to studies on population differentiation that is overlooked when viewing only gene-pools.Most biological species are subdivided into populations that are more or less strongly connected by gene flow. This facilitates a species' persistence via adaptive differentiation to local conditions, which in turn serves to maintain genetic variation for future adaptational processes. This concept of species is reflected, for example, in meta-population analysis with its special emphasis on extinction-recolonization dynamics (see [1]
Spatiogenetic characteristics of beech stands with different degrees of autochthony
Hans-Rolf Gregorius, Dierk Kownatzki
BMC Ecology , 2005, DOI: 10.1186/1472-6785-5-8
Abstract: Permutation analyses show that correlations between spatial distances and genetic differences vary only little in the studied beech stands. In view of the popularity of this and related descriptors of spatiogenetic covariation, this result came as a surprise. The newly developed methods lead to a different conclusion. Significant spatiogenetic structure is indicated in all stands when considering the mean and variance of spatiogenetic separation, where separation is measured by the smallest spatiogenetic difference of an individual from all others. Spatiogenetic difference is measured here by a combination of the spatial distances and genetic differences between individuals. This descriptor indicates the existence of spatiogenetic clusters in the beech stands. In order to arrive at an explicit representation of cluster structure as a representation of subpopulation structure, two types of cluster structure (primary and α-isolated) are distinguished, both of which reflect desirable characteristics of subpopulation structure. Particularly in the α-isolated structure, the proportion of individuals organized in clusters, the effective size, and the effective number of clusters clearly distinguish and consistently rank the four stands with respect to their types of forest management and the associated criteria of autochthony.The surprisingly high correspondence between our descriptors of spatiogenetic structure and forest management types confirms the appropriateness of the applied measure of cluster isolation and of the criterion for the choice of the level α of cluster isolation. The two types of cluster structure and their characteristic descriptors are thus suggested to be promising tools for the detection of subpopulation structure. To include the effects of long-distance gene flow, the presented methods can be extended as outlined to larger spatial scales in order to detect higher order population structure.Autochthony is generally considered for conspecific collec
Reinforcement of genetic coherence in a two-locus model
Hans-Rolf Gregorius, Wilfried Steiner
BMC Evolutionary Biology , 2001, DOI: 10.1186/1471-2148-1-2
Abstract: It is shown that mutants at the mating modifier locus, which increase heterotypic fusions but do not lower the homotpyic fusions relative to the resident allele at the object locus, generally replace the resident allele. Since heterozygote advantage at the object locus is a necessary condition for this result to hold true, reinforcement of genetic coherence can be claimed for this case. If the homotypic fusions are lowered, complex situations may arise which may favor or disfavor the mutant depending on initial frequencies and recombination rates. To allow for a generalized analysis including alternative models of genetic coherence as well as the estimation of its degrees in real populations, an operational concept for the measurement of this degree is developed. The resulting index is applied to the interpretation of data from crossing experiments in Alnus species designed to detect incompatibility relations.Anagenetic (phyletic) and cladogenetic evolution can be basically distinguished by the fact that during the former genetic variation is transformed within a single population without losing the reproductive contact between the genetic variants, while in the latter genetic variation is distributed to reproductively separated populations. In other words, phyletic evolution has the capacity to maintain or strengthen "genetic coherence" among the genetic variants. This coherence is lost as a consequence of reproductive separation during cladistic processes. The necessity to consider these complementary processes as of equal significance in evolutionary reasoning was recognized, for example, by [1] and becomes already evident in the running title "Can speciation be prevented?" of this paper. Contrary to common concepts, the title suggests the existence of persistently acting forces of genetic disjunction that have to be counteracted in order to maintain genetically variable reproductive communities.In its probably most obvious form the separation-coherence dualism b
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