Effect of Transition of Mounted Chisel Plow from Operation to Transport on Longitudinal Stability of Tractor (Part 1- Modeling)

In order to investigate the effect of transition of mounted implements from operation to transport on longitudinal stability of a tractor that works on sloping land, a mathematical model was developed. In this model two operation modes for a mounted chisel plow were considered: penetration of the plow into the soil and depth reduction of it, and the effects of transferred forces and torques from the plow on longitudinal stability index of tractor were studied. Longitudinal stability index of tractor was defined as the ratio of the dynamic load of tractor front axle to the static load of it when tractor is on level ground. To test the model, different geometries and mass specifications of tractor MF285 and chisel plow combination were used as the input parameters of the model. According to the results of this study, during plow penetration into the soil, internal forces of the connecting rods were zero and positive values were obtained for the internal force of the connecting rods during depth reduction of the plow; therefore, connecting rods acted only as pulling beams. Furthermore, when the plow depth was increased, the model predicted the increase of the force exerted on the center of gravity of tractor in X direction; however, the force exerted on the center of gravity of tractor in Z direction was almost not affected by the plow depth and height ratio variations. These results were expected and verified that the assumptions of the model have been rational. Moreover, longitudinal stability index of tractor during plow penetration was approximately constant. However at the moment of transition of the plow from operation to transport, this index was reduced abruptly. Therefore in situations that tractor works on steep slopes, plow transition from operation to transport should be avoided

Health Hazard Assessment of Tractor Driver Whole-body Vibration Utilizing the ISO 2631 Standard

In order to quantify tractor driver Whole-Body Vibration (WBV) induced by some of the agricultural operations, the ISO 2631 standard was utilized. Detailed methodology of the calculation of the WBV evaluating indices using the time-domain acceleration data analysis was presented. According to the results of the study, typical weighted root mean square (WRMS) value of the Z-axis vibration was more than the WRMS value of the X and Y axes vibrations. Furthermore all of the severity categories (SV) obtained from driving the tractor on asphalt road, plowing and power tilling based on the equivalent daily stress index (Sed), were graded in the class of 3 or 4; which means that the health hazard associated with these operations is marginal. Finally among the examined machines; the locally built, tractor front mounted, hydraulic power aided loader caused vibrations that were slightly higher than the exposure limit value (ELV), with regard to the parameter of WRMS over an eight hour period (A(8))

Time preferences and the pricing of complementary durables and consumables

There is strong empirical evidence that consumers discount at significantly higher rates than firms. Yet, most research abstracts from the effect of discount rates on marketing decisions such as pricing. We study the effects of a consumers' discount rate that is higher than a firm's discount rate on prices, profits and consumer surplus of complementary products in four competitive settings and an infinite time setting: the firm is a monopolist or competes in the durable market and either ties the consumable to the durable or sells untied products. Our analysis yields five main results: First, a higher time preference of consumers than the firm never increases the optimal durable price and never decreases the optimal consumable price. Second, the optimal consumable price of tied goods is always higher than the optimal consumable price of untied goods, whereas the optimal durable price is always higher when goods are untied. Third, a higher time preference of consumers than the firm never increases profit, always decreases consumer surplus and, as a result, always decreases welfare. Fourth, the ability of the firm to commit to future prices and of consumers to commit to future purchases benefits both consumers and the firm. Fifth, if the firm competes in the durable market, then tying increases consumer surplus when consumers commit to purchasing the consumable. We discuss the implications of our results for firms' pricing strategies

2-Approximation for Prize-Collecting Steiner Forest

Approximation algorithms for the prize-collecting Steiner forest problem (PCSF) have been a subject of research for over three decades, starting with the seminal works of Agrawal, Klein, and Ravi and Goemans and Williamson on Steiner forest and prize-collecting problems. In this paper, we propose and analyze a natural deterministic algorithm for PCSF that achieves a $2$-approximate solution in polynomial time. This represents a significant improvement compared to the previously best known algorithm with a $2.54$-approximation factor developed by Hajiaghayi and Jain in 2006. Furthermore, K{\"{o}}nemann, Olver, Pashkovich, Ravi, Swamy, and Vygen have established an integrality gap of at least $9/4$ for the natural LP relaxation for PCSF. However, we surpass this gap through the utilization of a combinatorial algorithm and a novel analysis technique. Since $2$ is the best known approximation guarantee for Steiner forest problem, which is a special case of PCSF, our result matches this factor and closes the gap between the Steiner forest problem and its generalized version, PCSF

Analisa Performa Klastering Data Besar pada Hadoop

Big Data is a collection of data with a large and complex size, consisting of various data types and obtained from various sources, overgrowing quickly. Some of the problems that will arise when processing big data, among others, are related to the storage and access of big data, which consists of various types of data with high complexity that are not able to be handled by the relational model. One technology that can solve the problem of storing and accessing big data is Hadoop. Hadoop is a technology that can store and process big data by distributing big data into several data partitions (data blocks). Problems arise when an analysis process requires all data spread out into one data entity, for example, in the data clustering process. One alternative solution is to do a parallel and scattered analysis, then perform a centralized analysis of the results of the scattered analysis. This study examines and analyzes two methods, namely K-Medoids Mapreduce and K-Modes without Mapreduce. The dataset used is a dataset about cars consisting of 3.5 million rows of data with 400MB distributed in a Hadoop Cluster (consisting of more than one engine). Hadoop has a MapReduce feature, consisting of 2 functions, namely map and reduce. The map function performs a selection to retrieve a key, value pairs, and returns a value in the form of a collection of key value pairs, and then the reduce function combines all key value pairs from several map functions. The results of the cluster quality evaluation are tested using the Silhouette Coefficient testing metric. The K-Medoids MapReduce algorithm for the car dataset gives a silhouette value of 0.99 with a total of 2 clusters

Methodological Analysis in Iranian Sociological Research

This research, evaluating social knowledge identity in terms of methodology in Iran, showed that the knowledge suffers from dislocation and complexity. From one hand, the knowledge followed by the social scholars has fallen far from its production, reproduction and fixation roots in developed countries, and the scholars do not observe the processes of the knowledge formation and just regard the consequences or results of the social knowledge. On the other hand, the knowledge is not concerned with conducting social setting and infrastructure in Iran; because this effort needs elites’ support and public interest at the same time and the condition has not fulfilled yet. Data of the research were gathered relied on logical bases of qualitative research, interpretive approach and abductive strategy, and by conducting directed qualitative content analysis through multiple purposive sampling, and rhetorical reading of the performed interviews and also of the 55 works conducted by six participants of the research

Pelatihan penggunaan aplikasi Inventaris Gudang Puskesmas Sakra

An inventory system is a system that manages data on items owned by an office. A good inventory system will help a company manage data on goods owned by the company. Not only do big companies need an inventory system, but small offices also need an inventory system. Likewise, with the Health Center, managing data such as drugs, medical equipment, stationery, etc., requires a good warehouse inventory system. Therefore, this service activity aims to develop and train the Health Center Warehouse Inventory application. The partner of this activity is the Sakra Community Health Center (administrative staff). The methods used are lectures, mentoring, and direct practice using applications. The result of this activity is the production of warehouse inventory system software for the Sakra Health Center. In addition, the Sakra Health Center's administrative staff can also run the softwareSistem inventaris merupakan suatu sistem yang mengelola data barang-barang yang dimiliki suatu kantor. Memiliki sistem inventaris yang baik akan membantu suatu perusahaan dalam mengelola data barang yang dimiliki oleh perusahaan tersebut. Tidak hanya perusahaan besar yang membutuhkan sistem inventaris, akan tetapi kantor yang kecil juga membutuhkan sistem inventaris. Demikian pula dengan Puskesmas, dalam mengelola data-data seperti obat, perlengkapan medis, alat tulis dan sebagainya membutuhkan sistem inventaris gudang yang baik. Oleh karena itu, kegiatan pengabdian ini bertujuan untuk mengembangkan dan memberikan pelatihan tentang aplikasi Inventaris Gudang Puskesmas. Mitra dari kegiatan ini adalah Puskesmas Sakra (tenaga administrasi). Metode yang digunakan yaitu ceramah, pendampingan, dan praktik langsung menggunakan aplikasi. Hasil dari pengabdian ini adalah terbentuknya produk perangkat lunak inventaris gudang Puskesmas Sakra, dan tenaga administrasi yang diberi pelatihan mampu mengoperasikan perangkat lunak tersebu