Hizir Sofyan

The application of fuzzy clustering to satellite images data

In this study, a fuzzy clustering method that we implemented in statistical software package (XploRe), GIS (GRASS) and remote sensing (ERDAS) were used to classify and preset multi-spectral Landsat TM images. Comparatively, the result of this investigation shows that the underlying structures and patterns from satellite images data can be classified more precisely than the conventional ones.

Econometric and Fuzzy Modelling of Indonesian Money Demand

Money demand is an important element of monetary policy analysis. Inflation is supposed to be a monetary phenomenon in the long run, and the empirical relation between money and prices is usually discussed in a money demand framework. The main purpose of money demand studies is to analyze if a stable money demand function exists in a specific country, especially when a major structural change has taken place. Examples for such structural changes are the monetary union of West Germany and the former German Democratic Republic in 1990 and the introduction of the Euro in 1999. There is broad evidence that money demand has been quite stable both in Germany and in the Euro area, see for example Wolters, Terasvirta and Lutkepohl (1998) and Holtemoller (2004a).

Online Prediction of Berlin Single-Family House Prices

SummarySingle-family houses are typically the most important component in their owners’ portfolios. Buying a home is a major financial transaction for most households. Yet, unlike assets traded in financial markets, getting a quote for the current market value of a house is not an easy task because houses are very heterogenous assets. They differ, among other things, in size, location, age and maintenance. In this paper, we describe a web-based, almost realtime prediction of prices for single family homes in Berlin, Germany. Based on an extended hedonic regression model and estimated from a rich data set covering all house transactions in Germany’s capital, this online service delivers predictions for homes with user-specified characteristics. We describe the statistical model and how its predictions are implemented on the computer to allow seamless interaction between its users and the data base containing the model estimates.

Classification and Regression Trees

We will call an estimator for the regression function defined by the CART methodology a regression tree. The word CART means classification and regression tree. This chapter will focus only on the regression trees.

Exposure to Traumatic Events and PTSD in a Postconflict and Disaster-Prone Area

ABSTRACT The present study examines lifetime exposure to traumatic events and the rate of PTSD among university students living in a postconflict and disaster-prone area. Two self-report questionnaires, namely the Life Events Checklist and a PTSD screening tool, were used in the study. PTSD was found in 21% of respondents. Approximately 96% of the respondents have been exposed to traumatic events during their lifetime. Both genders have the same rate of PTSD (p = 0.9) and exposure to traumatic events (p = 0.327). Findings suggest that lifetime exposures to traumatic events are high among students living in this region.

The use of Silica from beach sand as catalyst in Magnesium based hydrides for Hydrogen storage materials

Magnesium (Mg) as one of the potential candidate material for absorbing hydrogen, because theoretically has the ability to absorb large quantities of hydrogen 7,6 wt%. However, the kinetic reaction of Mg is very slow. Its takes 60 minutes to adsorp hydrogen with the operating temperature (adsorb/desorb) high of 350°C. Therefore, in this study discusses the hydrogen storage materials based on MgH2-SiO2. The purpose of this study to improve desorption temperature of hydrogen storage system based on MgH2. The main material is MgH2 combined with inserting SiO2 catalyst was successfully extracted from quartz sand with coprecipitation method. As for the material preparation process is done with the technique of mechanical alloying. Milling MgH2+SiO2 samples using a ball milling for 5 hours, with the ratio of ball to powder 10:1 and a speed of 400 rpm. By variation of the catalyst insertion of 1 wt%, 3 wt%, and 5 wt% of SiO2. The results of XRD measurement known that the sample was reduced to scale nanocrystal. Phase arising from the result of XRD observation are MgH2 phase as the main phase, and SiO2 phase as a minor phase. DSC testing results show that the lowest desorption temperature obtained on the sample with the addition of inserts weight of the catalyst 5 wt% SiO2 has milling for 5 hours which is equal 307,11°C.

Lessons Learned from Two Villages in the Tsunami Most Affected Area of Banda Aceh City; A Review of the Housing Reconstruction and the Current State of Village Development

This paper discusses two approaches to post-disaster housing reconstruction in Banda Aceh, the Indonesian area that was the most affected by the Indian Ocean Tsunami in 2004. The two villages discussed in this study are Alue Deah Tengoh and Lambung, both located in Meuraxa sub-district. The village of Alue Deah Tengoh represents the common approach to post-disaster reconstruction within in Aceh with the construction of housing carried out by several external benefactors. It is referred to as the donor driven approach. In contrast, the reconstruction of the village of Lambung was based on its community’s involvement. Contrasting these two approaches, this study analyzes time series satellite images, housing and other reconstruction archives. It also conducted site evaluation and depth interview with their leaders in order to evaluate the conditions of each village prior to tsunami as well as its current state of development. Our aim is to unravel the process of housing reconstruction in these respective locations village. Drawing from this analysis, our results evaluate these two distinct approaches to housing reconstruction in post-disaster Aceh. On the one hand, it reveals that the community-based approach adopted in Lambung enabled the successful use of land consolidation (LC) and the total makeover of village layout and housing plot arrangement. On the other hand, our study reveals that the donor approach in Alue Deah Tengoh resulted in a heterogeneous landscape with several types of houses contributing to social inequality and disparity. Moreover, the reconstruction of Alue Deah Tengoh did not include LC and kept the village old layout with its meandering narrow streets and poor accessibility. These features are bond to hinder the upgrading and maintenance of urban utility services as well as the evacuation process during future disasters. In the light of this study, we thus recommend that community driven approach should be implemented in post-disaster reconstruction programs.

Prevalence of depression and anxiety among college students living in a disaster-prone region

Highlights • College students experience various psychological problems.• Depression and anxiety are common among college students.• Depression and Anxiety was found in 18.8% and 27.4% of Indonesian college students, respectively.• Early detection and timely treatment should be beneficial to the students. Abstract The present study examined the prevalence rate of depression and anxiety among college students living in a disaster-prone area of Aceh, Indonesia. College students enrolled in two public Universities in Banda Aceh were randomly selected to participate in the self-administered standardized questionnaires for depression and anxiety. The prevalence rates of depression and anxiety were 18.8% and 27.4%, respectively. Depression was associated with gender and BMI while anxiety was only associated with gender. Depression is also positively correlated to anxiety. Depression and anxiety are prevalent among college students living in a disaster prone area. Early detection and timely treatment of mental disorders should be beneficial to the students living in this circumference.

Periodicity analysis of tourist arrivals to Banda Aceh using smoothing SARIMA approach

Forecasting the number of tourist arrivals who enters a region is needed for tourism businesses, economic and industrial policies, so that the statistical modeling needs to be conducted. Banda Aceh is the capital of Aceh province more economic activity is driven by the services sector, one of which is the tourism sector. Therefore, the prediction of the number of tourist arrivals is needed to develop further policies. The identification results indicate that the data arrival of foreign tourists to Banda Aceh to contain the trend and seasonal nature. Allegedly, the number of arrivals is influenced by external factors, such as economics, politics, and the holiday season caused the structural break in the data. Trend patterns are detected by using polynomial regression with quadratic and cubic approaches, while seasonal is detected by a periodic regression polynomial with quadratic and cubic approach. To model the data that has seasonal effects, one of the statistical methods that can be used is SARIMA (Seas...

Structure analysis of tax revenue and inflation rate in Banda Aceh using vector error correction model with multiple alpha

A country has several important parameters to achieve economic prosperity, such as tax revenue and inflation rate. One of the largest revenues of the State Budget in Indonesia comes from the tax sector. Meanwhile, the rate of inflation occurring in a country can be used as an indicator, to measure the good and bad economic problems faced by the country. Given the importance of tax revenue and inflation rate control in achieving economic prosperity, it is necessary to analyze the structure of tax revenue relations and inflation rate. This study aims to produce the best VECM (Vector Error Correction Model) with optimal lag using various alpha and perform structural analysis using the Impulse Response Function (IRF) of the VECM models to examine the relationship of tax revenue, and inflation in Banda Aceh. The results showed that the best model for the data of tax revenue and inflation rate in Banda Aceh City using alpha 0.01 is VECM with optimal lag 2, while the best model for data of tax revenue and inflation rate in Banda Aceh City using alpha 0.05 and 0,1 VECM with optimal lag 3. However, the VECM model with alpha 0.01 yielded four significant models of income tax model, inflation rate of Banda Aceh, inflation rate of health and inflation rate of education in Banda Aceh. While the VECM model with alpha 0.05 and 0.1 yielded one significant model that is income tax model. Based on the VECM models, then there are two structural analysis IRF which is formed to look at the relationship of tax revenue, and inflation in Banda Aceh, the IRF with VECM (2) and IRF with VECM (3).A country has several important parameters to achieve economic prosperity, such as tax revenue and inflation rate. One of the largest revenues of the State Budget in Indonesia comes from the tax sector. Meanwhile, the rate of inflation occurring in a country can be used as an indicator, to measure the good and bad economic problems faced by the country. Given the importance of tax revenue and inflation rate control in achieving economic prosperity, it is necessary to analyze the structure of tax revenue relations and inflation rate. This study aims to produce the best VECM (Vector Error Correction Model) with optimal lag using various alpha and perform structural analysis using the Impulse Response Function (IRF) of the VECM models to examine the relationship of tax revenue, and inflation in Banda Aceh. The results showed that the best model for the data of tax revenue and inflation rate in Banda Aceh City using alpha 0.01 is VECM with optimal lag 2, while the best model for data of tax revenue and inflat...