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Markus Stoffel - One of the best experts on this subject based on the ideXlab platform.

  • Impacts of land-cover changes on snow avalanche Activity in the French Alps
    'Elsevier BV', 2020
    Co-Authors: Mainieri Robin, Markus Stoffel, Favillier Adrien, Lopez Saez Jérôme, Eckert Nicolas, Zgheib Taline, Morel Pauline, Saulnier Mélanie, Luc Peiry Jean, Corona Christophe
    Abstract:

    International audienceDendrogeomorphic analyses provide long and continuous chronologies of mass movements that are useful for the detection of trends related to climate change. Socio-environmental changes can, however, induce non-stationarities. This study addresses the following questions: (1) How does the evolution of forest cover induce non-stationarities in tree-ring based reconstructions of snow avalanche Activity? (2) How are trends inherent to tree-ring approaches distinguishable from real fluctuations in avalanche Activity? Using dendrogeomorphic techniques, we reconstructed snow avalanches in six adjacent paths in the French Alps. Results show two distinct trends in Process Activity between 1750 and 2016. In the southern paths, the frequency of snow avalanches increased sharply in the 1970s. The distribution of tree ages, as well as old topographic maps, allow an attribution of this trend to the destruction of large parts of the forest stand by a large snow avalanche in the 1910-20 s. This extreme event induced a sudden change in the capability of newly colonizing trees to record subsequent snow avalanches. In the northern paths, by contrast, progressive afforestation starting in the mid-19th century, as well as colonization of the release areas after World War II, resulted in a strong reduction in snow avalanche Activity since the 1930s. Even if global warming remains a possible additional driver of snow avalanche Activity at the study sites, the rural exodus and the abatement of pastoral practices during the 19th and 20th centuries are the main explanations for the observed trends in Process Activity. Results also illustrate a need to clarify the complex interrelations among forest evolution, global warming, social practices, and the Process Activity itself when interpreting trends in mass movements. (C) 2020 Elsevier Ltd. All rights reserve

  • geomorphic control on regional glacier lake outburst flood and debris flow Activity over northern tien shan
    Grid and Pervasive Computing, 2019
    Co-Authors: V Zaginaev, Markus Stoffel, Dmitry Petrakov, S Erokhin, A Meleshko, Juan Antonio Ballesteroscanovas
    Abstract:

    Abstract Glacier lake outburst floods (GLOFs) and related debris flows (DF) are significant natural threats in the Tien Shan Mountains. Their occurrence is favoured by the formation of new glacier lakes and the destabilization of moraines and hillslopes due to climate warming. Understanding the frequency-magnitude of these Processes is essential for the implementation of Disaster Risk Reduction strategies. Yet, long-term records of past GLOFs or DF in the region are almost completely missing, which renders rational hazard and risk assessments difficult. Here, we present a unique, multi-century dataset of regional GLOF-DF reconstruction for the Tien Shan based on tree-ring analyses from six different torrential fans, and provide insights on regional Processes Activity. Based on this dataset, we also test whether GLOF-DF Activity is related to glacier degradation and changes in geomorphic characteristics at the catchment scale. Results from >430 disturbed trees growing on six different DF fans suggest frequent GLOF-DF Activity since the 19th century, which is consistent with available historical records. We also observe an increase in Process Activity during the mid-20th century coinciding with phases of glacier stagnation or even slight glacier advances. This means GLOF-DF Activity in northern Tien Shan is inversely related to moraine-glacier ratios as well as to glacier area shrinkage rates and fan characteristics (such as slope and depositional area). These findings imply that glaciological and geomorphic features could be used for regional susceptibility assessments in the future. Results presented here are the longest, annually resolved GLOF-DF series in the region, if not worldwide, and constitute a unique dataset to understand Process variability. As such, they should be used for further climate change adaptation to mitigate natural hazard and risk in the region.

  • deciphering dendroecological fingerprints of geomorphic Process Activity
    2017
    Co-Authors: Markus Stoffel, Juan Antonio Ballesteroscanovas, Christophe Corona, Karel Silhan
    Abstract:

    The initial employment of tree rings in geomorphic studies was simply as a dating tool and rarely exploited other environmental information and records of damage induced by earth surface Processes within the tree. However, these unique, annually resolved, tree-ring records preserve valuable archives of past Process Activity on timescales of decades to centuries. As many of these Processes also represent significant natural hazards, understanding their distribution, timing and controls provides valuable information that can assist in the prediction, mitigation and defence against these hazards and their effects on society. This chapter provides an introduction to the topics, and illustrates it with three case-study examples, demonstrating the application of tree-ring records in studying earth-surface Processes and illustrating the breadth and diverse applications of contemporary dendrogeomorphology. It also underlines the growing potential to expand dendrogeomorphic research, possibly leading to the establishment of a range of techniques and approaches that may become standard practice in the analysis and understanding of earth-surface Processes and related natural hazards in the future.

  • testing dendrogeomorphic approaches and thresholds to reconstruct snow avalanche Activity in the făgăras mountains romanian carpathians
    Quaternary Geochronology, 2015
    Co-Authors: Patrick Chiroiu, Markus Stoffel, Alexandru Onaca, Petru Urdea
    Abstract:

    Snow avalanches are a widespread natural phenomenon in steep mountain environments, where they modulate landscapes and frequently disturb forest stands. Such disturbances in trees have been used since the 1970s to retrospectively date avalanches, study their extent and reach, as well as to document their triggers. Although virtually every dendrogeomorphic paper is still based on the concepts established by Shroder (1978), important methodological improvements have been achieved in the field ever since and more particularly over the last decade. This study therefore reports on recent methodological progress and employs three different approaches (i.e. Shroder index value and Kogelnig-Mayer weighted index value) and different sets of signals in trees (i.e. inclusion of tangential rows of traumatic resin ducts as evidence of past avalanching) to record snow avalanche Activity. Using 238 increment cores from 105 Picea abies (L.) Karst trees which colonize a snow avalanche path in the Romanian Carpathians, we illustrate possibilities and limitations of the different approaches for the period covered by the chronologies (1852–2013). In addition, we sampled 30 undisturbed P. abies trees from a forest stand north of the avalanche path, where no geomorphic disturbance was identified, so as to build a reference tree-ring chronology. The three avalanche chronologies constructed with the disturbed trees allow identification of past Process Activity, but results differ quite considerably in terms of avalanche frequency, number of reconstructed events and their temporal distribution. Depending on the approach used, 15 to 20 snow avalanches can be reconstructed, with the best results being obtained in the dataset including tangential rows of traumatic resin ducts. The addition of this anatomical feature, formed after mechanical impact enlarges the number of growth disturbances by 43.5%, and can thus explain the increase of reconstructed avalanches by one-third as compared to the results of the chronology using the “conventional” Shroder approach.

  • possibilities and limitations of dendrogeomorphic time series reconstructions on sites influenced by debris flows and frequent snow avalanche Activity
    Arctic Antarctic and Alpine Research, 2011
    Co-Authors: Barbara Kogelnigmayer, Markus Stoffel, Michelle Schneuwlybollschweiler, Johannes Hubl, Florian Rudolfmiklau
    Abstract:

    Past debris-flow and snow avalanche Activity was assessed for the Reiselehnrinne (Tyrol, Austria) using growth disturbances in growth-ring series of 372 Norway spruce (Picea abies (L.) Karst.) trees. Determination of events was performed by analyzing (a) the number and (b) intensity of growth disturbances within tree-ring series and (c) the spatial distribution of affected trees. Differentiation of debris flow from snow avalanche events was based on the intra-annual position of scars, callus tissues or tangential rows of traumatic resin ducts, and on the spatial distribution of trees with simultaneous reactions in the tree-ring series. We introduce a weighting factor to substantiate the dating of past Process Activity in a comprehensive way and to compare individual events as to their intensity and total number of tree-ring responses. The accuracy of the dendrogeomorphic assessment was then evaluated by comparing the reconstructed event frequency with chronologies available for the Reiselehnrinne. Comparison of tree-ring with historical data demonstrated clearly that the reconstructed event frequency contains the majority of past debris flow and snow avalanche events in the Reiselehnrinne, but that dating of events is not always possible, especially if they are clustered in time or have a limited spread on the cone.

Singgih, Moses Laksono - One of the best experts on this subject based on the ideXlab platform.

  • Implementation Lean Manufacturing Method of Plywood Manufacture Company
    'Lembaga Penelitian dan Pengabdian kepada Masyarakat ITS', 2021
    Co-Authors: Koh Jastine, Singgih, Moses Laksono
    Abstract:

    The Plywood company in this study was able to produce 6,000m3/ year of plywood, but during 2018 and 2019 this company was only able to provide 2,905.14 m3/year and 1,120.73 m3/year. Production in 2018 and 2019 is far below the production capacity. This research will apply the lean manufacturing concept in the production Process of a plywood company. This research uses value stream mapping (VSM), value stream analysis tools (VALSAT), Process Activity mapping (PAM), Pareto diagrams, and root cause analysis. It is found extreme categories that occur in many Processes, namely Processing production and inventory. The recommendations given are to reduce employees and provide adequate storage. The future state VSM shows that a change in a lead time of 68%, and the reduction of the production Process is 248.18 minutes. 

  • Perbaikan Proses Produksi Jerrycan 5 Liter di PT. KEMASAN Menggunakan Pendekatan Lean Manufacturing
    'Lembaga Penelitian dan Pengabdian kepada Masyarakat ITS', 2021
    Co-Authors: Pontiana Aisyah, Singgih, Moses Laksono
    Abstract:

    PT. KEMASAN adalah perusahaan manufaktur yang bergerak dalam produksi packaging plastik. Produk jerrycan 5 liter merupakan produk yang paling banyak dipesan oleh customer VVIP dan diproduksi secara kontinu. Pada kondisi aktual terdapat permasalahan yang dapat menurunkan kepuasan pelanggan dilihat dari complaint berupa ketidaksesuaian produk, produk defect melebihi standar 3%, persentase breakdown melebihi standar 2.5%, dan adanya keterlambatan pengiriman produk jerrycan 5 liter sebanyak sembilan kali pada tahun 2019. Permasalahan-permasalahan tersebut dapat menurunkan kepercayaan konsumen dan bahkan menyebabkan kerugian finansial. Adanya defect dan breakdown merupakan indikasi pemborosan pada proses produksi yang dapat dikurangi melalui pendekatan lean manufacturing. Penelitian dimulai dari identifikasi proses produksi dan waste dengan tools value stream mapping, Process Activity mapping, observasi, dan diskusi dengan perusahaan. Kemudian dilakukan penentuan waste kritis dengan metode Borda dan didapatkan hasil waste kritis yaitu waste defect dan waste unnecessary motion. Selanjutnya dilakukan analisis akar penyebab waste kritis dengan metode 5 why’s dan dilakukan penentuan kategori risiko dengan FMEA untuk kemudian dibuat rekomendasi perbaikan. Diusulkan 3 alternatif perbaikan dan kombinasinya untuk kemudian dilipih alternatif terbaik menggunakan pendekatan value analysis. Dengan penerapan alternatif terpilih dihasilkan future state value stream mapping dengan penurunan lead time dari 3058 detik menjadi 2898 detik dan nilai value added bertambah sebanyak 1.2%

  • Work Efficiency Improvement in the Bidding Process
    'Lembaga Penelitian dan Pengabdian kepada Masyarakat ITS', 2021
    Co-Authors: Kelasworoningrum, Diana F., Singgih, Moses Laksono
    Abstract:

    A higher of competition level requires each company to increase its competitive advantage to be a market leader. One of the options to improve the competitive advantage is to increase company performance efficiency since using this option, operational cost can be reduced. In this particular study, Lean Service concept is applied to eliminate waste that occurs throughout the value stream of bidding Process in order to improve procurement performance in terms of its efficiency in PT XYZ. Lean concept implementation started from creating the Value Stream Mapping (VSM) to map current value stream along the bidding Process continued with Process Activity Mapping (PAM) to classify waste that occurs throughout the value stream, Borda Count Method (BCM) to determine the critical waste and Root Cause Analysis (RCA) to find the root cause with risk analysis approach which can be used as a reference to determine priority of improvement. The goal of this study is work efficiency improvement in the bidding Process by identifying its waste and its root cause since by recognizing those waste, improvement plan can be formulated. This study generates recommendations for improvement plan namely designing SOP which not only standardize its Processes moreover set its time limit and improvement in the management system by increasing coordination with end user as well as upgrading procurement knowledge. Those result might be utilized by organization to increase procurement’s work efficiency

Hamdala Ihwan - One of the best experts on this subject based on the ideXlab platform.

  • IMPLEMENTASI METODE VALUE STREAM MAPPING SEBAGAI UPAYA MEMINIMALKAN WASTE (Studi Kasus: Subbagian Assembly di PT Selatan Jadi Jaya, Sidoarjo)
    Program Studi Teknik Industri Fakultas Teknik Universitas Brawijaya, 2015
    Co-Authors: Musyahidah Brisky, Choiri Mochamad, Hamdala Ihwan
    Abstract:

    Abstrak   PT Selatan Jadi Jaya merupakan perusahaan yang memproduksi battery yang dijual di dalam negeri maupun luar negeri. Dalam subbagian assembly PT SJJ masih terdapat beberapa permasalahan yang dapat dikategorikan sebagai waste. Dalam penelitian ini metode yang digunakan adalah Value Stream Mapping, untuk memudahkan dalam proses identifikasi waste digunakan metode Process Activity Mapping (PAM). Waste yang telah diidentifikasi dikelompokkan menurut kategori seven waste. Seven waste tersebut kemudian dirangking dengan metode Waste Assessment Model (WAM). Hasil akhir dari metode WAM dikali dengan frekuensi terjadinya waste, dipilihlah proses dengan bobot waste tertinggi. Proses terpilih adalah proses heat sealing. Dilakukan analisa akar penyebab waste dengan diagram Ishikawa. Berdasarkan akar penyebab waste, maka dirancanglah usulan perbaikan. Perbaikan pertama yang diusulkan berupa perancangan sistem kanban, usulan perbaikan kedua yaitu perancangan palet, usulan perbaikan ketiga adalah pemberian alat pelindung diri berupa ear plug kepada operator. Setelah diberikan usulan rekomendasi maka dapat digambarkan prediksi future state map. Kata kunci: Value Stream Mapping, Seven Waste, Process Activity Mapping, Waste Assessment Model, Kanban

Choiri M. - One of the best experts on this subject based on the ideXlab platform.

  • Implementasi Metode Value Stream Mapping Sebagai Upaya Meminimalkan Waste (Studi Kasus: Subbagian Assembly Di PT Selatan Jadi Jaya, Sidoarjo)
    'Brawijaya University', 2015
    Co-Authors: Musyahidah B., Choiri M.
    Abstract:

    PT Selatan Jadi Jaya merupakan Perusahaan yang memproduksi battery yang dijual di dalam negeri maupun luar negeri. Dalam subbagian assembly PT SJJ masih terdapat beberapa permasalahan yang dapat dikategorikan sebagai waste. Dalam penelitian ini metode yang digunakan adalah Value Stream Mapping, untuk memudahkan dalam proses identifikasi waste digunakan metode Process Activity Mapping (PAM). Waste yang telah diidentifikasi dikelompokkan menurut kategori seven waste. Seven waste tersebut kemudian dirangking dengan metode Waste Assessment Model (WAM). Hasil akhir dari metode WAM dikali dengan frekuensi terjadinya waste, dipilihlah proses dengan bobot waste tertinggi. Proses terpilih adalah proses heat sealing. Dilakukan analisa akar penyebab waste dengan diagram Ishikawa. Berdasarkan akar penyebab waste, maka dirancanglah usulan perbaikan. Perbaikan pertama yang diusulkan berupa perancangan sistem kanban, usulan perbaikan kedua yaitu perancangan palet, usulan perbaikan ketiga adalah pemberian alat pelindung diri berupa ear plug kepada operator. Setelah diberikan usulan rekomendasi maka dapat digambarkan prediksi future state map

Listyo Juliance Nugrahaningrum - One of the best experts on this subject based on the ideXlab platform.

  • PENERAPAN LEAN MANUFACTURING UNTUK MEMINIMASI WASTE WAITING PADA PROSES PRODUKSI BUKU SOFT COVER DI PT MIZAN GRAFIKA SARANA
    Universitas Telkom S1 Teknik Industri, 2018
    Co-Authors: Listyo Juliance Nugrahaningrum
    Abstract:

    PT Mizan Grafika Sarana merupakan perusahaan yang bergerak di bidang percetakan buku. Dalam penelitian ini, jenis buku yang diteliti berfokus pada buku soft cover. Berdasarkan data yang didapat dari perusahaan, terdapat permasalahan keterlambatan pengiriman buku soft cover hampir setiap bulan selama tahun 2017. Dengan adanya permasalahan tersebut, menggunakan pendekatan lean manufacturing, dilakukan identifikasi proses produksi melalui pemetaan value stream mapping (VSM) current state dan Process Activity mapping (PAM). Melalui identifikasi tersebut, didapatkan hasil identifikasi adanya waste waiting sebesar 9%. Oleh karena itu, perlu dilakukan rancangan perbaikan untuk meminimasi waste waiting. Selanjutnya, untuk mengetahui akar penyebab waste waiting, dilakukan identifikasi menggunakan fishbone diagram dan 5 why’s. Tahap penyelesaian masalah untuk akar penyebab waste waiting menggunakan tools manufacturing, salah satunya adalah SMED. Usulan rancangan perbaikan untuk meminimasi waste waiting pada workstation pencetakan adalah penambahan operator untuk aktivitas changeover pergantian plate, penjadwalan pergantian sparepart smash blanket pada interval waktu yang telah ditentukan, pemberian lembar checksheet maintenance, dan visual control berupa poster. Berdasarkan rancangan usulan perbaikan, selanjutnya dilakukan pemetaan value stream mapping (VSM) future state sehingga didapat lead time berkurang menjadi 10924,115 detik (3,03 jam). Kata Kunci : Soft Cover Book, Lean Manufacturing, Waste Waiting, Fishbone Diagram, 5 Why\u27s, Value Stream Mapping, Process Activity Mapping, SME