Material Procurement Research Articles

Evaluasi pengelolaan dana Bantuan Operasional Sekolah (BOS) di SD Negeri 76 Manado

The School Operational Assistance (BOS) program is an initiative of the Indonesian government to support school operational costs and improve the quality of education. However, in its implementation, misuse of funds often occurs which affects accountability. Based on this problem, this study aims to evaluate the mechanism of management, use and accountability of BOS funds with the research object SD Negeri 76 Manado based on Permendikbudristek Number 63 of 2023. The research method used was descriptive qualitative, with data collected through interview sessions and documentation. The results showed that the BOS fund management mechanism at SD Negeri 76 Manado had followed the applicable regulations, but there were several obstacles such as changes in the price of goods that affected budget planning. In the use of funds, allocations were made in stages for two semesters and adjusted based on an evaluation of actual needs. Accountability is carried out through a report on the realization of the use of funds prepared every semester. The study concludes that despite efforts to manage funds transparency and accountability, improvements are still needed in supervision and planning adjustments to overcome external constraints and ensure more efficient use of funds. In relation to unforeseen needs, including the cost of emergency repairs, health and security costs, and the procurement of additional teaching materials, there was no effective mechanism for managing the use of BOS funds.

COMPRESSIVE STRENGTH PREDICTION FOR SELF-COMPACTING CONCRETE USING ARTIFICIAL NEURAL NETWORKS

This study investigates the relationship between concrete constituent materials, slump values, density, strain and compressive strength. The database was set in the laboratory by performing a quality assurance test on the constituent materials to ascertain their suitability for concrete work. For material procurement and selection, the British Standard Department of Environment DOE technique of concrete trial mix designs was used. In this study, twelve concrete mixes were utilized. Two simplified models were developed using the feedback network Artificial Neural Networks architecture (ANNs) with R version 4.0.5 and R studio version 1.2.5033. In the two models, an independent layer comprising six nodes and a dependent layer comprising two nodes were taken. Having carried out the sensitivity analysis, the capacity of the developed equation was evaluated in terms of error metrics MSE and RMSE. The grading envelope for river sand showed that the graph fell perfectly into grading envelope zone 2 while other constituent materials tested were all confirmed suitable for concrete works. The results of compressive strength were obtained from varied water-cement ratios used for the concrete trial mix design which ranges between 0.45 to 0.6. The compressive strength results showed that the results increased consistently for each design mix. It is worthy of note that the strength of the mix fell between grades 15, 20, 25 and 35 respectively for both the 7-day and 28-day strength accordingly. Conversely, the ANN models predicted both 7-day and 28-day strength close to the laboratory value. It is concluded that this research has demonstrated economic viability which would enhance overall construction planning efficiency for future researchers, consultants and contractors in the building industries.

Development of a prototype to evaluate and monitor energy efficiency aiming at power quality 4.0

In research and development projects, the need to implement prototypes to speed up the development and delivery process is paramount, offering tools to validate scenarios and anticipate challenges. The aim of this research is to experimentally develop a prototype for monitoring electrical power systems using a gateway that converts MODBUS-RTU communication protocols to TCP, providing useful information for technicians and managers of a company in the Manaus Industrial Estate (PIM) in the field of reflective tapes. To achieve this goal, it was necessary to specify the technical requirements for panel assembly and communication via MODBUS, acquire and research materials in accordance with the technical specifications and technological requirements, implement the monitoring system with an IMS Controller for reactive power compensation, and configure and parameterise the MODBUS protocol via the RTU to TCP converter. The prototype is expected to be able to take accurate measurements and, in the data acquisition process, obtain readings of electrical quantities such as: voltage per phase; current per phase; power factor per phase; active power per phase; reactive power per phase; apparent power per phase; frequency; voltage THD and voltage harmonics. The prototype must act intelligently to drive the capacitor bank to control and monitor reactive power. The development of the prototype included crucial stages such as the specification of technical requirements, the acquisition of suitable materials, and the implementation and configuration of the system. The specification ensured that the components were aligned with the project objectives, while the procurement of materials ensured the quality and efficiency of the system. The implementation of the Automatic Reactive Power Compensation Controller was vital for reactive power compensation and the configuration of the MODBUS protocol ensured precise communication between the components. To summarise, this project demonstrates the importance of prototypes in technological advancement, offering practical and efficient solutions for industry. The prototype developed to monitor electrical power systems through a MODBUS-RTU to TCP protocol converter gateway represents a significant advance, providing essential data and contributing to informed decision-making, improving the performance and management of the company's energy resources.

Optimizing construction supply chains through AI: Streamlining material procurement and logistics for project success

Optimizing construction supply chains through AI: Streamlining material procurement and logistics for project success

Efficiency Strategy for Procurement of Raw Materials for Side Beam for Bogie with Material Requirement Planning at PT XYZ

Companies in Indonesia must find the right solution in order to survive and compete in the era of globalization. Price competition is an important strategy in the competition between similar companies. Based on this, there is a need for a good understanding in the company regarding strategic financing planning in order to achieve predetermined goals efficiently. This efficiency can be characterized by minimal cost expenditure in order to obtain maximum profit. One way to get maximum profit is by implementing good inventory management PT XYZ is a train manufacturing company in Southeast Asia. The company produces various types of trains. There is a production planning for the Train XYZ project with a total production of 526 units of train components for the Side Beam for Bogie. Procurement of these raw materials, PT XYZ uses Lot for Lot (LFL) at a cost of Rp1,411,402. The use of the LFL system still has shortcomings, namely problems due to late delivery and inefficient procurement in terms of financing. The results of production planning research with several MRP methods that have been compared, it is concluded that POQ lot sizing is the most efficient procurement of raw materials other than LFL. In detail, the total cost with the POQ method amounted to Rp1,243,140 and decreased by 11.9%. The cost consists of procurement costs of Rp781,162 and storage costs of Rp461,978.

Optimization of Raw Material Inventory using Always Better Control (ABC) Analysis and Economic Order Quantity (EOQ) Method Approach in the Warehouse of a Bolt Manufacturing Factory in Indonesia

There is a problem in the raw material procurement process at the Contractor Company, such as running out and excess stock of raw materials, as well as difficulties in determining how many raw materials to order that meet the company's economic value. Running out of raw material stock results in delays in production activities, while excess raw material stock can fill warehouse capacity, thereby increasing storage costs. To overcome this problem, research was carried out using a quantitative descriptive method to determine the level of production cost efficiency and production effectiveness level in order to achieve optimization of raw material supplies using Always Better Control (ABC) Analysis and the Economic Order Quantity (EOQ) Method at Bolt Companies. ABC analysis plays a role in determining which raw materials have the highest level of demand and the EOQ method plays a role in determining the amount of raw materials to be ordered in order to meet the company's economic value. The research results show that the combination of ABC Analysis and EOQ Method can reduce ordering costs and raw material inventory. There are 4 items out of 10 raw material items that are included in Category A or the most prioritized category. From the results of calculations using the EOQ method, the Bolt Company can save total orders and raw material inventory (TIC) in the period January to December 2023 amounting to IDR 2,147,403,-.

Research on Risk-Averse Procurement Optimization of Emergency Supplies for Mine Thermodynamic Disasters

Reducing procurement risks to ensure the supply of emergency supplies is crucial for mitigating the losses caused by mine thermodynamic disasters. The risk preference of decision-makers and supply chain collaboration are the important aspects for this reductiom. In this study, a novel P-CVaR (Piecewise conditional risk value) distributionally robust optimization model is proposed to accurately assist the decision-makers’ decision of risk preference for reducing procurement risks. Meanwhile, the role of cooperation between procurement and reserves are considered for the weakening procurement risks. A risk-averse bi-level optimization model is proposed to obtain the optimal procurement strategy. Furthermore, by applying the Lagrange duality theorem, the complexity of the bi-level optimization model is simplified then solved using a PSO algorithm. Using empirical analysis, it has been verified that the model presented in this paper serves as a valuable guideline for mine thermodynamic pre-disaster emergency material procurement strategies for the prevention of thermodynamic disasters.

Carbon Footprint for Jeans’ Circular Economy Model Using Bagasse

To date, clothing has been produced and disposed of in large quantities. It is also known that each process, from the procurement of raw materials to production, transportation, sales, laundry, and disposal, has a significant environmental impact. According to the Global Fashion Agenda, greenhouse gas (GHG) emissions from the fashion industry account for 4% of the global total. Therefore, apparel makers are shifting from a linear economy to a circular economy. For example, the Japanese start-up Curelabo Co., Ltd. (Okinawa, Japan) developed jeans (bagasse washi jeans) made from bagasse, which is a residual material derived from sugarcane after the extraction of cane juice. Furthermore, the use of improved dyeing reduces boiler fuel consumption and eliminates the need for detergents and acid. For disposal, the used jeans and their production waste are processed into biochar for carbon sequestration. In this study, we attempted to calculate GHG emissions using life cycle assessment (LCA) for the circular economy model developed by Curelabo Co., Ltd. GHG emissions from the production of bagasse washi jeans were 1.09 × 101 kg-CO2e. Dyeing, bleaching, and fabric finishing, known as the wet processes, were found to contribute a large proportion of GHG emissions due to their high energy consumption. Furthermore, the entire lifecycle of GHG emissions from bagasse washi jeans, including transport, sales, laundry, and disposal, were 1.53 × 101 kg-CO2e. First, the use of bagasse washi yarn for the weft reduced by 2.99 × 10−1 kg-CO2e compared with the use of conventional 100% bleached cotton yarn. Second, compared with conventional dyeing, GHG emissions from the improved dyeing process were reduced by 2.78 kg-CO2e. Third, the disposal of the used jeans and their production waste into biochar reduced GHG emissions by 9.01 × 10−1 kg-CO2e. Additionally, GHG emissions can be reduced by re-inputting waste in the paper-making process and by using liquefied natural gas as boiler fuel in the dyeing process.

Analisis dan Pemodelan Proses Bisnis Katering pada UMKM Menggunakan BPMN

Fafiras Kitchen is a family business that focuses on food catering services. This business involves three main operational stages, namely the ordering process, procurement of raw materials, and delivery of products to customers. From the results of observations and interviews, several problems were identified such as the absence of good records in the ordering process resulting in errors in order fulfillment and loss of customer data, dependence on one raw material supplier increases the risk of delays and disruptions in the supply chain and inefficient delivery management caused by human error and no real time tracking, so this has an impact on customer loyalty. This research aims to analyze and model the current business process and provide recommendations for improvement. Modeling is done using Business Process Model and Notation (BPMN) with a qualitative approach to investigate existing business processes. The results of this research can identify areas of improvement to increase the efficiency and effectiveness of MSMEs operations so that MSMEs can better understand, manage, and optimize their business processes. In addition, this research also conducted simulations using the Bizagi Modeler application to test the validity of the business process modeling that has been made. The simulation results show an increase in time in the implementation of business processes.

Raw Materials and Lithic Production During the Early Magdalenian in Cantabrian Spain: Cova Rosa (Ribadesella, Asturias)

The lithic assemblage studied here comes from Cova Rosa, one of the main Upper Palaeolithic sites in Asturias (northern Spain). The remains were found in Layer B5, which was excavated by F. Jordá Cerdá and A. Gómez Fuentes in 1978 and are associated with an osseous assemblage and archaeozoological remains. This occupation has been dated by radiocarbon to about 16,400 BP (ca. 19.8–19.6 ka cal BP), corresponding to Archaic/Lower Magdalenian. The present study combines the determination of the raw materials and the identification of the production systems to achieve an understanding of the management of lithic resources by hunter-gatherer groups in the Late Pleistocene. The sourcing of mostly local materials (mainly Piloña flint), the wide variety of rock types of diverse provenances (up to 10 types), and the presence of well-represented lithological tracers (Flysch, Chalosse) turn Cova Rosa into an important case for studying different lithic raw material procurement models. The predominance of microlaminar production and the variability in the exploitation strategies used to obtain backed tools, as well as the poor standardisation of flake production, follow the dynamics observed in other occupations of similar chronology in a wide geographical area that includes Cantabrian Spain and south-west France.

Optimizing Production Planning and Inventory Management in Post-Pandemic Recovery Using A Multi-Period Hybrid Uncertain Optimization Model

During the post-COVID-19 pandemic recovery phase, decision-makers in the manufacturing and retail sectors are confronted with numerous uncertainties. These issues comprise various aspects of operations, including the acquisition of raw materials or components and planning production activities. Therefore, this research aimed to introduce an innovative dynamic hybrid optimization model that combined probabilistic and fuzzy techniques. The model would offer a solution for addressing the challenges posed by uncertain parameters, particularly in the context of post-pandemic scenarios for production planning and inventory management with multiple periods of observation. The model was designed to handle exceptional circumstances such as parameter uncertainties, augmented demand fluctuations, fuzzy variables, and probabilistic factors. The primary objective of the model was to maximize the expected total profit of the operational process. To achieve this aim, an uncertain programming algorithm based on the interior point method was used to compute the optimal decision for the problem at hand. Through the execution of simulations using randomly generated data, the proposed model was thoroughly evaluated and analyzed with six suppliers, three raw part types, three product types, and six periods. All six suppliers were selected to supply raw parts, however, not all suppliers were selected to supply particular raw part types. Furthermore, it was derived that the expectation of the maximum profit is 897261.40; this is the best expected profit generated by the optimization model, meaning that other decisions may result in a smaller expectation of the profit. The results of these simulations unequivocally showed the effectiveness of the decision-making model in providing optimal solutions, specifically in terms of raw material procurement and production planning strategies. Subsequently, this model could serve as a valuable tool for decision-makers operating within the manufacturing and retail industries.

Preschool teachers’ perceptions of STEAM-based learning in Banda Aceh

The purpose of this study was to identify early childhood teachers' perceptions of STEAM-based learning. This qualitative research will be analyzed descriptively, and semi-structured interviews with open-ended questions will be conducted with four early childhood education (ECE) teachers in Banda Aceh. The findings show that ECE teachers' perceptions of STEAM-based learning techniques have a high potential to be implemented in Banda Aceh City ECEs, as the respondents have used aspects of STEAM in their learning. Teachers' lack of knowledge of STEAM-based learning approaches and procurement of materials and funds to fulfil STEAM learning needs are barriers to integrating STEAM in ECE institutions in Banda Aceh. More STEAM socialization and STEAM learning implementation training is needed for ECE teachers in Aceh in general.

OPTIMASI BIAYA DISTRIBUSI MATERIAL BATAKO DENGAN METODE NORTH WEST CORNER DAN STEPPING STONE PADA PERUMAHAN DI KOTA AMBON

In construction projects, distribution costs for material procurement support the design process of a projects and are also very influential and determine project planning. It is also necessary to utilize costs as optimally as possible to anticipate losses to the company due to the problem of distributing material from the supply to the projects location. In a project, materials needed in large quantities cannot always be met by just one material source. Because of this, several material sources are needed to meet the needed to meet the needs of a project, for this reason this research was carried out using two transportaastion methods, North West Corner fot initial solution and Stepping Stone for the optimum solution. With the aim of calculating material distribution costs to find optimal prices from galunggung, suli banda, and passo to housing demand locations in Ambon City, namely kusu-kusu, suli and upper halong. From the results of the above topic, it can be concluded that optimizing the distribution costs of brick material to housing in Ambon City using th initial North West Corner method obtained a distribution cost of Rp. 349,200.000 and using and advanced method, namely Stepping Stone which has been optimized, resulting in a cost of Rp. 274,655,000 this results in savings of Rp. 74,545.000.Keywords:Cost Optimasion, Housing, Material Distribution, North Westh Corner, Stepping Stone,

Pengendalian Persediaan Bahan Baku Bawang Merah Untuk Produksi Bawang Goreng Dengan Metode Economic Order Quantity (EOQ) Dan Just In Time (JIT)

Effective planning to manage the procurement of raw materials is crucial for maintaining productivity in production activities and controlling costs. Indonesian enterprise UD. XYZ is dedicated to the manufacturing of fried onions. However, between April 2022 and June 2023, there have been regular fluctuations in the raw material availability for the production process, which has resulted in subpar output levels and unmet demand. To solve this problem, this study will use time series forecasting techniques to estimate the demand for fried onions and the Economic Order Quantity method to control raw material supply. Furthermore, this study uses the Just In Time approach to determine the minimum inventory cost. Both systems are anticipated to lessen the effects of changes in raw material availability. Based on the research results, the linear regression method was used for forecasting, which predicted an average demand of 1354 Kg of fried onions with a MAPE value of 2,79%, MAD 27,59, and MSD 1317,81. Then, an EOQ value of 1992,85 kg was calculated using the Economic Order Quantity (EOQ) and Just In Time (JIT) methods. This resulted in a total minimum storage cost of Rp. 2.989.271.

Feed industry: transfer of new technologies

Relevance – the industry for production of compound feed for farm animals is the main link in the structure of the AIC, located in the middle of all production and technological connections of the livestock products market. Over the past decade, quite high indicators have been achieved in feed production in the republic. The main components are the increase in consumption of grain fodder by livestock industry, increase in production volume of the main components of feed preparation, and optimization of the procurement of raw materials. The goal is to show the realities and prospects for increasing the potential of feed industry in Kazakhstan, the need for effective strategies based on intensification and innovative technology renewal. Methods – comparative, statistical, system analysis, logical generalization. Results - the authors state that enterprises that have become the main suppliers of raw materials for livestock sector have a number of economic difficulties that do not allow them to meet the growing needs of agroindustrial production and create reserves for large-scale export of combined feed and livestock products to the world market, in particular in countries of the Middle East. There is a significant dependence of feed production on cereals, since the key type of raw material source is 5 grade grain (coarse). Therefore, it is necessary to expand the area under these crops to obtain the required volumes of grain mixtures and feed. It is noted that one of the main promising areas of innovative activity remains the issue of reducing cost of operating equipment and energy costs. Conclusions - organization of highly efficient feed production segment in the country is necessary for proportional and balanced development of grain processing enterprises - main components of grain and meat product subcomplexes and the links between them. It is necessary to increase the capacity of large production enterprises to provide feed products on industrial scale, and also to apply technologies based on the use of grass flour and molasses from grains, which contain a high proportion of elements with high energy value, which can significantly increase the efficiency of raising livestock and reduce product costs.

An optimal raw material procurement strategy that minimizes enterprise price risks

This article is devoted to the problem of theoretical and information support for decision-making in strategic management of raw material procurement processes. The study is timely, because there is currently significant volatility in prices for raw materials. This poses very difficult challenges for managers. Finding solutions is one of the most important areas of business informatics. This article discusses a procurement strategy in two stages: at the beginning and middle of the month. The price of raw materials is known only at the beginning of the month. Price is a continuous random variable. You can predict only the interval of its change. Here the interval is directly used to determine the purchase volume at a known price. The authors derived a functional dependence of the maximum risk according to Savage on the amount of purchased raw materials at the beginning of the month. As a result, it was possible to establish the amount of raw materials to be purchased at the beginning of the month to reduce maximum risk to a minimum. Using the example of corn purchases, we carried out a comparative analysis of possible methods for determining these intervals based on an analysis of price time series. The findings are useful for managers of processing enterprises. This work is the first to solve the problem of minimizing the maximum risk when purchasing raw materials.

STITCHING COSTS TOGETHER: THE LOGISTICS BEHIND TEXTILE PRICING

Logistics' capacity to efficiently handle the flow of resources, information, and items from point of origin to point of consumption makes it an indispensable tool in many facets of business and daily life. This article explores the significant impact of logistics costs on textile pricing, considering factors like transportation, warehousing, customs, handling, supply chain efficiency, technological integration, environmental regulations, economic and political influences. Efficient supply chain management is vital, as it covers stages from raw material procurement to product distribution. This articles also highlights the importance of managing modes of transportation, warehousing, customs compliance and packaging. The role of technology and sustainability in reducing costs is emphasized, along with the impact of economic and political factors. The study underscores the necessity of optimizing logistics to maintain competitive pricing and enhance market for the textile products.

Analysis of Raw Material Procurement and Production In The Bandung Nukasep Household Bread Industry In The Pedati Market, Central Bengkulu District

Salah satu industri rumah tangga di Kabupaten Bengkulu Tengah adalah usaha pembuatan Roti Bakar Bandung Nukasep yang berproduksi setiap hari. Penelitian ini bertujuan mengetahui pengadaan bahan baku Roti Bakar Bandung Nukasep dan untuk mengetahui apa saja faktor produksi Roti Bakar Bandung Nukasep di Pasar Pedati Kabupaten Bengkulu Tengah. Motode yang digunakan dalam penelitian ini adalah deskriptif kualitatif yang mana data-data didapatkan dari observasi, wawancara dan data skunder. Berdasarkan hasil penelitian dan teori-teori yang melandasi masalah yang dibahas maka pengadaan bahan baku Roti Bakar Bandung Nukasep di Pasar Pedati Kabupaten Bengkulu Tengah menerapkan komponen enam tepat, yaitu tepat kuantitas (jumlah roti bakar yang diproduksi setiap harinya rata-rata 312 bungkus), tepat kualitas (tepung bermerek cakra kembar), tepat tempat (lokasi pembelian bahan baku di toko rempah sari Pasar Minggu Kota Bengkulu), tepat waktu (satu minggu sekali), tepat harga (untuk sekali pembelian sebesar Rp. 6.262.000), dan tepat jenis (menggunakan tepung yang berprotein tinggi). Dan faktor produksi Roti Bakar Bandung Nukasep di Pasar Pedati Kabupaten Bengkulu Tengah meliputi bahan baku, modal, tenaga kerja, lama usaha,dan permintaan.

The Stone Age of Qeqertarsuup Tunua (Disko Bugt). A regional analysis of the Saqqaq and Dorset cultures of Central West Greenland

The present text is a revised version of the Ph.D. thesis ‘Tent Rings and Stone Tools’ defended by the author on March 11th 2005 at the University of Copenhagen. Saqqaq and Dorset sites excavated by the author in the southern part of Qeqertarsuup Tunua (Disko Bugt) form the empirical basis for a comparison of Saqqaq and Dorset settlement in the area. Earlier reconstructions of the cultural history were based mainly on observations of stratified middens. In contrast to this, the present work focuses on the ‘horizontal dimension’ within the archaeological record. As a consequence, settlement patterns, dwelling types and the spatial organisation of dwellings are the principal objectives. Saqqaq and Dorset settlement patterns are broadly similar and it is concluded that there is little evidence to suggest any major difference in economy or adaptation between the two periods. Both Saqqaq and Dorset settlement patterns are characterised by a number of large settlements located strategically near the most productive biotopes. Minor settlements, most often occupied during the warm season, are found within the catchment area, indicating annual recurring dispersal of the population during the warmer months. Only Sydostbugten, in Southeastern Qeqertarsuup Tunua, appears to exhibit significant differences between Saqqaq and Dorset settlement patterns. Large Dorset settlements have not been found in Sydostbugten and it is suggested that this area, probably due to climatic oscillations, was less attractive for settlement during the Dorset period than it was in the Saqqaq. Consequently, the Dorset people seem only to have utilised Sydostbugten for specialised seasonal camps. Saqqaq and Dorset accommodation comprises distinct summer and winter dwellings. During both periods, the summer dwellings are characterised by what are believed to be single family tents. These occur in two principal varieties: Tent rings, with a central hearth, and mid-passage tent rings, where the interior is divided in two by parallel lines of stones. This difference in architecture is suggested to result from variation in the social composition of the inhabitants. Winter dwellings of both the Saqqaq and Dorset cultures are characterised by more solidly built structures. In the Saqqaq culture there are ‘platform dwellings’ and mid-passage structures filled with fire-cracked rocks. During the Dorset, the winter dwellings are characterised by ‘double-platform dwellings’, in which a central floor area divides the interior into two platforms that are often paved. The presence of more than one hearth or lamp stand, as well as ‘mirrored’ distributions of the most frequent tool categories to the left and right of the central floor area, is interpreted as a result of these dwellings being occupied by two families. Chapter 7 focuses on Saqqaq raw material distribution from killiaq sources in the vicinity of Qaarsut and Angissat. The raw material distribution from these two sources is characterised as a regional and local system. The procurement and subsequent distribution of raw materials from Angissat in Southern Qeqertarsuup Tunua appears thus to have been imbedded in the local resource exploitation. Much of the raw material extraction appears to have been carried out by hunting parties visiting the outcrop during summer hunting trips. In contrast to this, Qaarsut at Nuussuaq shows evidence of a more comprehensive production of preforms, which were distributed through-out Western Greenland. Economically as well as socially, there appear to be numerous similarities between the Saqqaq and Dorset cultures. However, when evaluating the radiocarbon dates, there appears to be discontinuity between the two periods as is also suggested by earlier excavations of stratified deposits. In Sisimiut District, to the south of Qeqertarsuup Tunua, the latest Saqqaq dates overlap with the oldest Dorset dates. Theoretically, there could be continuity between the two periods outside Qeqertarsuup Tunua, however the archaeological evidence for such a development has yet to be found. When the cultural history of Qeqertarsuup Tunua is compared with that of Peary Land, the dwelling types and chronological units appear very similar. In the case of Dorset and Independence II, the similarities also extend to include the lithic inventory. As a consequence it is difficult to maintain a division between Dorset in Western and Southern Greenland and Independence II in the High Arctic.

Sieci neuronowe do mapowania archeologicznych artefaktów litowych

An analytical non-destructive strategy to chemically characterize lithic artefacts has been developed. Around 100 archaeological lithic materials found in Neolithic-Chalcolithic sites in the Mediterranean region of the Iberian Peninsula and nowadays stored in different museums of the Valencian Community (Spain), were studied. The materials belong to different typologies of rock (diabase, sillimanite, ophite and amphibolite) and were analysed employing portable energy dispersive X-ray fluorescence spectroscopy (pXRF) directly in the rock surface. The obtained data were processed through neural networks protocol, specifically the so-called Kohonen networks or Self Organised Maps (SOM), to map the geologic samples. This self-organized topological feature maps are suitable to deal with multidimensional representations and map them in a two-dimensional space of neurons, following an unsupervised learning protocol. SOM is used to reduce multidimensional data onto lower-dimensional spaces and clustering procedures. As a result, SOM create spatially organized representations, which enhance the discovery of correlations between data. In this case the method has enabled the evaluation of elemental markers related to each rock type behaving as a fine hidden pattern detector and so understand the possible advantages and disadvantages of the analytical method employed to define provenance issues. The attribution suggested by statistics is mainly driven by the composition of rocks essential minerals which are linked to the different petrogenetic conditions. The results showed that in most of the cases the distribution and dispersion of the chemical profile depend of the kind of rock, and clearly suggest that a good way to identify stone tools raw material procurement is to look for elemental markers, being the prior step to create an approximation to ancient exchange networks and their evolution in a diachronic axis.