A new algorithm for recognizing the unknot

The topological underpinnings are presented for a new algorithm which answers the question: `Is a given knot the unknot?' The algorithm uses the braid foliation technology of Bennequin and of Birman and Menasco. The approach is to consider the knot as a closed braid, and to use the fact that a knot is unknotted if and only if it is the boundary of a disc with a combinatorial foliation. The main problems which are solved in this paper are: how to systematically enumerate combinatorial braid foliations of a disc; how to verify whether a combinatorial foliation can be realized by an embedded disc; how to find a word in the the braid group whose conjugacy class represents the boundary of the embedded disc; how to check whether the given knot is isotopic to one of the enumerated examples; and finally, how to know when we can stop checking and be sure that our example is not the unknot.Comment: 46 pages. Published copy, also available at http://www.maths.warwick.ac.uk/gt/GTVol2/paper9.abs.htm

Kajian Hujan–aliran Menggunakan Model Hec–hms di Sub Daerah Aliran Sungai Wuryantoro Wonogiri, Jawa Tengah

Model HEC-HMS untuk perhitungan hujan-aliran di DAS terdiri atas masukan berupa hujan dan karakteristik DAS serta aliran sebagai keluaran. Tujuan penelitian ini adalah 1) mengetahui karakteristik fisik DAS berupa nilai curve number (CN), 2) mengetahui karakteristik aliran (debit puncak, volume outflow dan waktu puncak) hasil hidrograf banjir model HEC-HMS dengan hidrograf banjir terukur. Penentuan CN komposit DAS menggunakan pendekatan SCS-CN. Parameter awal model dengan HEC-GeoHMS menghasilkan alur elemen model dan nilai parameter awal (CN komposit, persentase impervious area dan time lag). Analisis hidrograf banjir model HEC-HMS meliputi perhitungan runoff dengan model SCS-CN, direct runoff menggunakan SCS UH dan baseflow menggunakan resesi eksponensial. Hasil penelitian ini menunjukkan nilai CN komposit Sub DAS Wuryantoro pada tahun 2010 sebesar 69,53 pada kondisi AMC II. Hasil hidrograf banjir model HEC-HMS memberikan nilai sangat baik dengan objective function sebesar 0,24% untuk selisih debit puncak, 1,85% untuk selisih volume outflow dan waktu puncak sama

Analisis Kecelakaan Kerja Dengan Metode Failure Mode and Effect Analysis (Fmea) Studi Kasus : Automotive Workshop Semarang

Automotive Workshop is a business unit that specializes in repair, painting and maintenance of vehicles. This workshop services body repair, modification custom paint, color matching service and car detailing. Work done in the workshop often caused accidents for the mechanics. Over last 3 years the accidents recorded in the Automotive Workshop like a wound, hammered hand, slipped foot, irritation from welding exhaust, electric shock etc. To response the issues at the Automotive Workshop, the researcher do analyze the work accident using Failure Mode and Effect Analysis (FMEA). The purpose of this study is to predict the potential dangers that can occur, evaluate the impact of hazards, and establish corrective actions that can be taken to prevent or reduce the chances of accidents would happened. FMEA method will help identify sources and root causes of a problem and then it can be seen which of these causes is a priority and then it will be improved in order to increase the effectiveness of the production process. The highest RPN number is 25 obtained the type of work accidents among which are hands exposed stainless ruler bracket, head exposed sponge, eye irritation due to flue gas welding and hand electrocute

Community Structure of Seagrass Meadows in Mantehage Island Waters, North Sulawesi

Research on the structure of seagrass communities in the waters of the island Mantehage was conducted in September 2010. The purpose of this study is to collect data and information on the structure of seagrass communities. Observations includes the identification seagrass species, measuring the number of individual/stand, cover percentage of each type/species on the transect. 6 types of seagrass found, i.e. Enhalus acoroides, Halophila ovalis, Thalassia hemprichii, Thalassodendron ciliatum, Cymodocea rotundata and Syringodium isoetifolium. Seagrass species composition and distribution varies at each location and is dominated by the presence of Thalassia hemprichii (48.14%) with coverage percentage ranges between 15.91% to 35.11%. Diversity index values ranged from 0.79 to 1.69 ; evenness index between 0.57 to 0.94 and the index of dominance between 0.20 to 0.56. In conclusion, the condition of seagrass meadows in Mantehage island is relatively good and can support marine life adequately

Pengembangan Model Interface Decision Support System Manajemen Pemeliharaan Jalan Berbasis Data Mining

Sistem Manajemen Perkerasan Jalan modern harus mampu melakukan interpretasi, prediksi, optimasi dan dukungan keputusan yang kuat bagi stake holder. Hal tersebut dapat diwujudkan apabila seluruh data historis dan kondisi eksisting dapat dipetakan secara terintegrasi dengan baik. Diperlukan pengembangan konsep Decision Support System (DSS) yang mampu memberikan gambaran implementasi integrasi antara proses interpretasi dan optimasi pemeliharaan jalan. Pendekatan yang dipilih adalah pengembangan model Geographic Information System (GIS) dengan piranti lunak open source. Data yang digunakan adalah sistem pemeliharaan jalan eksisting di Pulau Jawa. Konsep ini berupa model sebagai aplikasi antar muka yang mampu menerima input berupa numeric dan koordinat kemudian memberikan output berupa text, numeric, tabular, dan grafis. Metode yang digunakan adalah melakukan integrasi dan simulasi rangkaian pengolahan big data, proses optimasi, menjadi sebuah tampilan sederhana. Konsep model GIS yang kembangkan dengan melakukan integrasi Data mining (DM) dan optimasi, mampu menampilkan aplikasi interface yang sederhana dan dapat memberikan kemudahan para stake holder untuk melaksanakan sistem manajemen perkerasan jalan dengan langkah sederhana dan menyeluruh

Faktor-faktor yang Mempengaruhi Profitabilitas pada Lkm UED SP di Kecamatan Rambah Samo Kabupaten Rokan Hulu

This study aims to determine the financial performance of Microfinance Institutions UED SP in Rambah Samo District and determine the factors that affect the profitability of the Microfinance Institutions . Data processing is done by calculating the geometry and panel data regression analysis . There are 11 UED SP which is the object of this research . The results using geometry formulas indicate that the UED SP in Rambah Samo District has financial ratios ROA and CAR that meets the ideal standar interim financial ratios LDR NPL and ROA is still not ideal. Factors that affect the profitability of Microfinance Institutions UED SP in Rambah Samo District is LDR as variable of liquidity and NPL as variable of credit crunch

Bambu sebagai Bahan Konstruksi Rangka Dinding Rumah Tembok Suku Bajo di Desa Kabalutan dalam Upaya Perbaikan Hunian

Suku Bajo adalah salah suku laut yang banyak bermukim di sepanjang perairan pulau Sulawesi, salah satunya yang menetap di desa Kabalutan kepulauan Togian. Desa Kabalutan adalah suatu pemukiman yang bangun di atas pulau-pulau karang sehingga sebahagian besar hunian masyarakat berada di atas permuaan air laut dan beberapa rumah didirikan di atas daratan dari bukit karang yang diratakan. Kawasan ini sangat jauh dari ibu kota Kabupaten Tojo Una-una yaitu Ampana, daerah ini dapat dicapai dengan perjalanan laut sekitar 4 -5 jam, sehingga pengadaan bahan-bahan konstruksi menjadi barang sangat mahal dan langka. Tujuan dari penelitian ini adalah menerapkan ipteks bagi masyarakat Bajo dalam penggunaan bahan lokal utamanya bambu sebagai bahan konstruksi rumah Tinggal. Metode yang digunakan adalah penyuluhan dan praktek langsung yang dilakukan dalam beberapa tahap, dimulai tahap penentuan disain, mengolah bambu sebagai rangka dinding, selanjunya plasteran dinding dan finising. Hasil akhir adalah rumah yang estetik, sehat, ekonomis/murah, ramah lingkungan, struktur kuat dan awet. Kata Kunci: Konstruksi Rangka Dinding Bambu, Rumah Tembok, Suku Baj

Long term effect of renal denervation on 24 hour abpm blood pressure variability and blood pressure load parameters

The aim of the study was to evaluate the long-term effect of renal sympathetic denervation (RSD) on 24h ambulatory blood pressure measurement (ABPM) and blood pressure load (BP load) in patients with resistant hypertension. The study included 32 patients with treatment-resistant hypertension and performed successful RSD. The effect of renal denervation was significant both in terms of daytime, nighttime and 24-hour arterial pressure, with the most pronounced effect on nocturnal blood pressure. In addition to mean BP reduction we found out a significant improvement of weighted 24 h SD and BP load during follow-up. A long-term effect of the RSD, reported as a reduction in 24-hour systolic blood pressure above 10 mm Hg at month 12, was found in 22 patients (68.8%). In multivariate regression analysis, two parameters remained predictive for successful renal denervation – higher nighttime systolic blood pressure (OR 0.9, 95% CI 0.8-1.005, p = 0.05) and lower pulse pressure (OR 1.13, 95% CI 1.01-1.26, p = 0.03)

Analisis USAhatani dan Kemampuan Membayar Kredit pada Petani Karet Eks Upp Tcsdp Taluk Kuantan Sub Unit Muara Lembu

The objectives of this research are to analysis of rubber farming system and loan repayment ability of rubber plantation of the farmers ex UPP TCSDP in Sub Unit Muara Lembu, Kuantan Singingi Regency. Survey method was conducted in 3 villages, involved Muara Lembu, Koto baru and Logas rubber farmers. Rubber plantation farmers taken by purposive amount 30 farmers as respondents, distributed 10 farmers in each village.The research result showed, that the rubber production of ex TCSDP plantation was 2146 kg ojol/year. The household farmer income was Rp. 48.718.147/year in average and the expenditure of household farmer was Rp. 19.783.266/year in average. The rest of the farmers ' credit with interest until 2015 is Rp. 3.543.422. There were 28 samples that have the ability to pay > 1 which means being able to pay the credits, but the 21 samples has not paid off until today with the biggest reason is the loss of information where to pay the debt