Gabion as a coastal protection structure: a case study in Panjang Island Indonesia

Panjang Island is a small island in Jepara, Indonesia which is very vulnerable to coastal damage due to crashing waves. Therefore, presence of coastal protection structure is essentially important. Gabion structure was constructed to protect this coastal area. Considering the age, the existing gabion structure needed assessment and analysis to ensure its performance in term of protecting the coastal area. This study aimed at assessing and analyzing the performance of the existing gabion structure. Data of the study were collected through observing the condition of the structure. Assessment was carried out by scaling 1 (minor) to 5 (severe damage). Results of the analysis showed that the value of stability to overturning was 3.96, while the stability to shearing was 2.07, the structure stability was in safe category. Soil pressure under the structure in σ max. was 0.39 kg/cm2, while σ min was 0.16 kg/cm2, which means safe. The condition of gabion as a coastal protection structure in section 1 was partially damaged with a moderate level of damage, in section 2, the damage was revealed to be a minor level of damage, while in section 3, the damage was in a minor level of damage.

Pavement structure assessment from the multi-source data of a moving vehicle

This paper proposed a novel assessment method for pavement structural status based on the multi-source data of a moving vehicle. The classification of pavement on subgrade (POS) and pavement on bridge deck (PBD) was taken as an example. A mobile acquisition system was designed to collect multi-source data. Vehicle accelerations on PBD and POS were analyzed, and some features were selected to build 15 Support Vector Machine (SVM) classifiers. Results show that some features are helpful, including vehicle speed, maximum value, minimum value, standard deviation of accelerations at time domain, and three peak frequencies at frequency domain. The accuracy was 91.67%. Then some sections were tested by a falling weight deflectometer (FWD) to verify the structural differences between POS and PBD. Accordingly, this paper initially generated the method for pavement structural analysis by vehicle vibration. This method can be referred to for more detailed pavement structural analysis in the future.

Advances in visual soil evaluation techniques

Soil structure is a complex and dynamic soil property that constitutes a key aspect of soil health. Soil structure assessment can be evaluated in the field by visual soil evaluation techniques. Development and improvement of these techniques/methods have been the focus of numerous soil scientists worldwide since the mid-20th century. Divided into topsoil and soil profile methods, they differ in principle and level of detail of the assessment. The development and protocols of selected methods are presented in this chapter in chronological order of development, to show differences in methodological approaches. The description given for each of the methods includes guidance for the appropriate selection of the method to be used by stakeholders. Two case studies are given as examples of i) how visual techniques can contribute to achieving the challenges for developing sustainable agricultural management focused on nurturing soil fertility, and ii) the use of visual techniques as tools to assess and monitor soil health in developing countries.

SHADOW ECONOMIC ACTIVITY: ESSENCE, STRUCTURE, ASSESSMENT METHODS

the article is devoted to generalizing approaches to understanding the essence of shadow economic activity and its structure, assessing the duality of this phenomenon and describing the main methods of its assessment