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Abstrak :
Usaha para peneliti untuk menciptakan alat transportasi air (kapal) yang hemat energi terus dilakukan hingga saat ini. Modifikasi geometri, dimensi dan jumlah lambung merupakan suatu hal yang penting dalam usaha pengurangan hambatan kapal. Penggunaan Jenis kapal berlambung banyak katamaran dan trimaran mencapai angka 40% dari total kapal yang berlayar. Hambatan total kapal terdiri atas hambatan gesek dan hambatan sisa. Hambatan gesek merupakan fungsi dari geometris, perubahan tekanan, kekasaran permukaan dan coating pada permukaan lambung. Hambatan sisa fungsi dari gaya seret gelombang yang terbentuk oleh masing-masing lambung kapal. Dengan kemajuan ilmu material, diciptakan berbagai macam cat yang dapat berfungsi sebagai pelindung dinding kapal dan sebagai pengurang koefisien gesek. Kulit ikan belut yang mengandung lendir merupakan biopolimer yang ramah lingkungan dan tidak beracun. Tujuan dari penelitian ini yaitu mengetahui efek variasi pelekatan biopolimer kulit belut (Monopterus Albus) pada lambung model kapal monohull, katamaran asimetris dan trimaran asimetris terhadap hambatan total model kapal dengan variasi bilangan Froude. Model kapal monohull, katamaran dan trimaran dengan pendekatan displacement yang sama dan diberikan variasi posisi pelekatan kulit belut pada lambung model kapal ditarik dengan variasi kecepatan pada kolam percobaan. Variasi sarat dan trim digunakan pada percobaan ini. Pengukuran tegangan tali pada kecepatan kapal konstan (tercapainya terminal velocity) dilakukan dengan load cell transducer yang terhubung ke data akusisi. Percobaan dilakukan dengan teliti dan dilakukan pengulangan secepat mungkin untuk menghindari degradasi biopolimer lendir belut. Percobaan dilakukan pada air tawar dan perubahan temperatur seminimal mungkin (dijaga konstan). Hasil menunjukkan pelekatan biopolimer pada monohull menghasilkan drag reduction sebesar 8 % pada bilangan Re = 20.000. Pada kapal katamaran asimetris, S/L = 0,2 terjadi drag reduction sebesar 6 % pada bilangan Froude = 0,45. Pada kapal trimaran asimetris, S/L = 0,2 dan R/L = 0,0 terjadi drag reduction sebesar 10.4 % pada bilangan Froude = 0,35. Dimungkinkan efek biopolymer mempengaruhi distribusi kecepatan pada lapisan terluar (outer layer) sehingga laju kecepatan kapal bertambah. ......Up to present time researchers are still continuously attempting to create energy saving water transportation vehicles (ships). Geometry, dimensions and number of hulls modification is an important effort to reduce the resistance of ship. The use of multi-hull ships such as catamaran and trimaran has reached 40% of total sailing ships. Total ship resistance consists of frictional resistance and residual resistance. Frictional resistance is the function of geometrics, pressure changes, surface roughness and coating of the hull surface. Residual resistance is the function of wave dragging force created by individual hull. With the advancement of material science various kind of paints have been created that could act as hull protection and as frictional coefficient reducer. Eel skin contents mucus that is environmentally friendly and non-toxic. The objective of the research is to investigate the effects of Monopterus Albus biopolymer attachment variations on monohull, asymmetric catamaran, and asymmetric trimaran model hulls to ship model total resistance with variation of Froude numbers. Monohull, catamaran, and trimaran ship models with same displacement approach were attached with eel skin at various positions on their hulls, the ship models were towed with various speeds on the test basin. Variation of drafts and trims were applied on the experiment. The tensions of the towing string at constant ship speed (at the terminal velocity) were measured using load cell transducer which was connected to data acquisition. The experiment was conducted very carefully and repetitions were carried out very quickly in order to avoid the degradation of Monopterus Albus biopolymer. The experiment was carried out on fresh water with very little changes of temperatures (kept constant). The results showed the attachment of biopolymer on monohull produced 8% of drag reduction at Re number = 20.000. On asymmetric catamaran with S/L = 0.2 produced 6% drag reduction at Fr = 0.45. On asymmetric trimaran with S/L = 0.2, and R/L = 0.0 produced 10.4% drag reduction at Fr = 0.35. These results are due to the effect of biopolymer in distributing the velocity at the outer layers that increase the velocity of the ships.

Abstrak :
Penelitian ini membahas tentang model pengelolaan pelabuhan dan peningkatan kinerja logistik pada sektor industri pelabuhan di Indonesia. Penelitian ini dilakukan karena Indonesia memiliki potensi besar menjadi poros maritim dunia. Namun, efisiensi logistik pelabuhan masih belum memuaskan, hal ini terlihat dari kinerja dwelling time masih 5-6 hari, dan biaya logistik masih 24,64% dari produk domestik bruto. Model ini dibangun dari 9 variabel laten dan 33 variabel manifest. Keseluruhan variabel yang digunakan berdasarkan studi literatur dan hasil wawancara langsung dengan 20 praktisi/ahli di bidang logistik pelabuhan, dan melalui focus group discussion untuk memastikan keseluruhan indikator yang digunakan sesuai dengan kondisi dan karakteristik pelabuhan di indonesia. Untuk membangun dan menguji model, penelitian ini menggunakan metode Structural equation modeling dimana terdapat 15 hipotesis yang digunakan. Sebanyak 500 kuesioner yang didistribusikan ke berbagai stakeholders industri pelabuhan, Namun, hanya 260 kuesioner yang valid untuk dapat diproses lebih lanjut. Hasil perhitungan persamaan struktural diperoleh bahwa faktor political economic environment berpengaruh signifikan terhadap model pengelolaan pelabuhan, dan model pengelolaan pelabuhaan berupa pemisahan dengan tegas antara operator pelabuhan dan regulator pelabuhan dan pengembangan pelabuhan dalam bentuk konsesi berpengaruh signifikan terhadap infrastructure and port facility, hinterland accessibility, quality of services, integration information system, price and incentive strategy; efisiensi customs clearance and administration procedure. Dalam model ini, efisiensi customs clearance and administration procedure yang diintegrasikan dengan operator pelabuhan terbukti berpengaruh secara signifikan terhadap kinerja logistik pelabuhan melalui quality of services, integration information system. Model ini juga membuktikan bahwa Efisiensi customs clearance and administration procedure berpengaruh signifikan terhadap quality of services, integration information system, dan price and incentive strategy. Begitupula infrastructure and port facility terhadap quality of services; quality of services terhadap kinerja logistik pelabuhan; dan integration information system terhadap kinerja logistik pelabuhan; berpengaruh signifkan terhadap kinerja logistik pelabuhan. Sedangkan variabel yang menurut responden tidak berpengaruh signifikan adalah hinterland accessibility terhadap quality of services dan price and incentive strategy terhadap kinerja logistik pelabuhan. Selain itu, dari hasil pengujian signifikansi model menunjukkan bahwa untuk meningkatkan kinerja logistik pelabuhan ekpor-impor di indonesia, prioritas utama yang perlu dilakukan adalah integration information system antara operator dan customs baru kemudian dilakukan price and incentive strategy, quality of service, infrastructure and port facility, dan terakhir hinterland accessibility. ......This study discusses the port management model and improved logistics performance in the port industry sector in Indonesia. This research was conducted because Indonesia has great potential to become the world's maritime axis. However, the efficiency of port logistics is still not satisfactory, this can be seen from the dwelling time performance of still 5-6 days, and logistics costs still 24.64% of gross domestic product. This model was built from 9 latent variables and 33 manifest variables. All variables used are based on literature studies and the results of direct interviews with 20 practitioners/experts in the field of port logistics, and through a focus group discussion to ensure that all indicators used are by the conditions and characteristics of ports in Indonesia. To build and test the model, this study uses the Structural equation modeling method where there are 15 hypotheses used. A total of 500 questionnaires were distributed to various port industry stakeholders. However, only 260 questionnaires were valid for further processing. The results of structural equation calculations show that political-economic environment factors have a significant effect on the port management model, and port management models in the form of explicit separation between port operators and port regulators in the form of concessions have a significant effect on infrastructure and port facilities, hinterland accessibility, quality of services, integration of information system, price and incentive strategy, efficiency of customs clearance and administration procedure. In this model, the efficiency of customs clearance and administration procedures integrated with port operators has proven to have a significant effect on port logistics performance through the quality of services, integration information systems. This model also proves that the efficiency of customs clearance and administration procedures has a significant effect on the quality of services, integration of information systems, and price and incentive strategies. Also infrastructure and port facility for quality of services; quality of services to the performance of port logistics; and integration of information systems to port logistics performance; significant effect on port logistics performance. While the variables which according to respondents do not have a significant effect are hinterland accessibility to quality of services and price and incentive strategies to port logistics performance. In addition, the results of testing the significance of the model indicate that to improve the performance of import-export port logistics in Indonesia, the main priority that needs to be taken is the integration of information systems between operators and customs and then a price and incentive strategy, quality of service, infrastructure and port facilities, and finally the hinterland accessibility.

Abstrak :
Kapal tanker kimia adalah salah satu jenis alat transportasi laut yang memiliki multikompartemen untuk membawa berbagai bahan kimia cair dalam jumlah besar secara bersamaan dan mencegahnya bercampur. Studi ini membahas tentang kesulitan yang dialami oleh manajemen kapal tanker kimia dalam merencanakan rute kapal dan jadwal untuk memelihara persediaan karena karakteristik yang unik dan kendala operasional kapal tanker kimia. Sampai saat ini, belum ada model yang membahas perutean dan penjadwalan kapal tanker kimia untuk menjaga tingkat persediaan yang mempertimbangkan keunikan tersebut secara simultan. Menjembatani kesenjangan penelitian yang terjadi, model matematika baru inventory ship routing and stowage planning problem (ISRSPP) untuk kapal tanker kimia diusulkan. Idenya adalah untuk menggabungkan stowage planning, yang merupakan masalah operasional, ke dalam inventory ship routing, yang merupakan masalah taktis, sebagai problem perencanaan yang terintegrasi. Tujuannya adalah untuk menemukan solusi dengan total biaya perjalanan minimum. Untuk tujuan ini, problem tersebut diformulasikan sebagai mixed integer linear programming (MILP) dengan model waktu diskrit. Untuk menganalisis penerapan model dan kinerjanya, dikembangkan dua skenario, di mana pada skenario pertama, model ISRSPP diselesaikan secara utuh, sementara pada skenario kedua, hanya bagian model inventory ship routing yang diselesaikan. Kedua skenario tersebut diselesaikan dengan menggunakan solver komersial. Hasilnya mengkonfirmasi bahwa kedua problem perencanaan tersebut tidak dapat dipisahkan karena pemisahan akan berpotensi membuat rute dan jadwal armada kapal yang tidak fisibel untuk membuat rencana penyimpanan kargo. ......A chemical tanker is one type of ocean carriers which has multi-compartments to carry various liquid chemicals in bulk simultaneously and keep them from mixing. This study discusses the difficulties experienced by management of chemical tankers in planning vessels route and schedule to maintain inventory because of the unique characteristics and operational constraints of chemical tankers. To date, there is no existing models that address inventory routing and scheduling of chemical tankers accounts for the aforementioned uniqueness simultaneously. Bridging the research gap, a novel integrated mathematical model of inventory ship routing and stowage planning problem (ISRSPP) for chemical tankers is proposed. The idea is to combine stowage planning, which is an operational problem, into inventory ship routing, which is a tactical problem, as an integrated tactical planning. The objective is to find a solution with minimum total voyage costs. For this purpose, the problem is formulated as a mixed integer linear program with a discrete time model. To analyse the model applicability and performance, two scenarios is built. In the first scenario, the ISRSPP model was solved completely, while in the second one, only the inventory ship routing part of the ISRSPP model was solved. Both scenarios were solved using a commercial solver. The results confirm that stowage planning problem cannot be treated separately from inventory ship routing problem of chemical tankers because the separation will potentially lead us to create the fleet routes for which no feasible stowage plan can be made.

Abstrak :
Di Indonesia, kemampuan kawasan konservasi (KK) menjaga tutupan hutan masih setara dengan kawasan non konservasi seperti misalnya hutan tanaman industri. Dengan kapasitas pengelolaan dan anggaran yang relatif rendah, KK di Indonesia masih mengalami kesulitan untuk mencapai tujuan konservasi. Selain itu, konservasi di Indonesia masih dilihat sebagai beban untuk pembangunan. Pada studi ini, pendekatan baru yang mengombinasikan analisis linier dan system dynamics dilakukan untuk menemukan faktor penting yang mempengaruhi efektivitas pengelolaan taman nasional (TN). Data tekanan-kondisi-respon dari 43 TN darat di Indonesia digunakan untuk menglasifikasi TN, mengidentifikasi faktor penting dan membangun model yang lebih efektif untuk pengelolaan KK. Tekanan dihitung dengan metode Human Footprint untuk tahun 2012 dan 2017. Kondisi adalah kondisi tutupan hutan dan respon adalah input pengelolaan TN. Studi ini memperlihatkan bahwa taman nasional darat di Indonesia dapat dikelompokkan dengan ciri kondisi tutupan hutan, anggaran, jumlah polisi kehutanan serta ketinggian dan kemiringan maksimal kawasan. Tutupan hutan yang baik disertai dengan anggaran dan jumlah polisi kehutanan yang meningkat. Tutupan hutan dipengaruhi secara signifikan oleh tekanan Human Footprint di dalam kawasan. Pemanfaatan jasa lingkungan di kawasan taman nasional berpengaruh positif pada kondisi tutupan hutan. Mengelola dengan baik semua variabel penting tersebut akan meningkatkan tutupan hutan di kawasan konservasi. ......In Indonesia, the ability of protected areas (PAs) to conserve forest is still equal to non-PAs such as industrial forest. Having relatively low management capacities and budget, Indonesia’s PAs are still having difficulties to achieve the conservation goals. Also conservation in Indonesia is still viewed as burden to development. In this study, a new approach of combining linier and system dynamics analyses were used to find the important factors affecting national parks (NPs) management effectiveness. Pressures-state-responses data from 43 terrestrial NPs in Indonesia were used to classify NPs, identified their important factors and developed more effective model for PAs management. Pressures were defined using Human Footprint method for 2012 and 2017. State was forest cover condition and responses were NPs management inputs. This study showed that terrestrial national parks in Indonesia can be grouped by characteristics of forest cover conditions, management budget, number of forest guards and maximum elevation and slope of the area. Good forest cover is accompanied by increased budget and number of forest guards. Forest cover is significantly affected by Human Footprint pressure within the park area. Environmental services in the national park area has a very positive effect on forest cover. Managing properly all of these important variables will increase forest cover in conservation areas.