On deficiency problems for graphs

Motivated by analogous questions in the setting of Steiner triple systems and Latin squares, Nenadov, Sudakov and Wagner [Completion and deficiency problems, Journal of Combinatorial Theory Series B, 2020] recently introduced the notion of graph deficiency. Given a global spanning property $\mathcal P$ and a graph $G$ , the deficiency $\text{def}(G)$ of the graph $G$ with respect to the property $\mathcal P$ is the smallest non-negative integer t such that the join $G*K_t$ has property $\mathcal P$ . In particular, Nenadov, Sudakov and Wagner raised the question of determining how many edges an n-vertex graph $G$ needs to ensure $G*K_t$ contains a $K_r$ -factor (for any fixed $r\geq 3$ ). In this paper, we resolve their problem fully. We also give an analogous result that forces $G*K_t$ to contain any fixed bipartite $(n+t)$ -vertex graph of bounded degree and small bandwidth.

Jackknife empirical likelihood: small bandwidth, sparse network and high-dimensional asymptotics

Summary This article aims to shed light on inference problems for statistical models under alternative or nonstandard asymptotic frameworks from the perspective of the jackknife empirical likelihood. Examples include small-bandwidth asymptotics for semiparametric inference and goodness-of-fit testing, sparse-network asymptotics, many-covariates asymptotics for regression models, and many-weak-instruments asymptotics for instrumental variable regression. We first establish Wilks’ theorem for the jackknife empirical likelihood statistic in a general semiparametric inference problem under the conventional asymptotics. We then show that the jackknife empirical likelihood statistic may lose asymptotic pivotalness in the above nonstandard asymptotic frameworks, and argue that this phenomenon can be understood in terms of the emergence of Efron & Stein (1981)’s bias of the jackknife variance estimator at first order. Finally, we propose a modification of the jackknife empirical likelihood to recover asymptotic pivotalness under both conventional and nonstandard asymptotics. Our modification works for all of the above examples and provides a unified framework for investigating nonstandard asymptotic problems.

Sistem Pemantauan Kapasitas Sampah Berbasis IoT (SiKaSiT) untuk Pencegahan Banjir di Wilayah Sungai Citarum Bojongsoang Kabupaten Bandung

ABSTRACTThe needs of flood disaster management encourage various efforts from all scientific disciplines of science, technology, and society. This article discusses the efforts to prevent flooding due to the habit of disposing of their waste into rivers through an innovative waste management system using the approach and application of Internet-based technology (IoT). Previous research has produced a prototype of the waste level monitoring system. In this research, the prototype was developed into a practical technology, called SiKaSiT (IoT Based Trash Capacity Monitoring System). This technology aims to assist janitor in monitoring, controlling and obtaining information about trash capacity and disposal time easily through an application on the smartphone in real-time and online. The system was made using a level detection sensor integrated with NodeMCU and Wi-Fi, MQTTbroker-protocol and Android-based application. Furthermore, the system was implemented in Bojongsoang adjacent to the Citarum river, where the water often overflowed due to the high rainfall and volume of trash around it. The results of system testing in the field shown good performance with value ranges of reliability is (99,785 - 99,944)% and availability is (99,786 - 99,945)%. SiKaSiT has several advantages over other similar systems. First, there is an application on the user's smartphone to monitor the capacity of trash and notification for full-bin. Second, the ability to operate on a small-bandwidth internet network because the throughput time is only around 0.59 kbps, thereby saving internet bandwidth consumption. This system has also helped overcome the problem of community trash management in Kampung Cijagra, where 60% of them gave feedback "agree" and the rest "strongly agree".Keywords: waste, IoT, monitoring, flooding, riverABSTRAKKebutuhan penanggulangan bencana banjir mendorong berbagai upaya dari semua disiplin ilmu baik dari bidang sains, teknologi dan sosial. Dalam artikel ini, penulis membahas upaya pencegahan banjir akibat kebiasaan membuang sampah ke sungai melalui inovasi sistem manajemen sampah menggunakan pendekatan dan penerapan teknologi berbasis Internet of Things (IoT). Pada riset sebelumnya telah dihasilkan sebuah prototype sistem monitoring level sampah. Kemudian pada riset ini prototype tersebut dikembangkan menjadi suatu teknologi tepat guna, dinamakan dengan SiKaSiT (Sistem Pemantauan Kapasitas Sampah Berbasis IoT). Teknologi ini bertujuan untuk membantu petugas kebersihan dalam memantau, mengontrol dan memperoleh informasi tentang kapasitas sampah dan waktu pembuangan sampah dengan mudah melalui aplikasi di smartphone secara real time dan online. Sistem dibuat dengan menggunakan sensor deteksi ketinggian sampah yang diintegrasikan dengan NodeMCU dan Wi-Fi, protokol MQTT broker dan aplikasi berbasis android pada smartphone. Selanjutnya sistem diimplementasikan di daerah Bojongsoang yang berdekatan dengan sungai Citarum yang airnya sering meluap akibat tingginya curah hujan dan volume sampah di sekitarnya. Hasil pengujian sistem di lapangan menunjukkan kinerja yang baik dengan kisaran nilai reliability adalah (99,785 – 99,944) % dan availability adalah (99,786 – 99,945) %. SiKaSiT memiliki beberapa kelebihan dibanding sistem serupa lainnya. Pertama, adanya aplikasi di smartphone pengguna untuk memonitor kapasitas sampah dan notifikasi saat tempat sampah penuh. Kedua, sistem mampu beroperasi pada jaringan internet bandwith kecil karena waktu throughput-nya hanya sekitar 0,59 kbps sehingga menghemat konsumsi bandwith internet. Sistem ini juga telah membantu menanggulangi permasalahan pengelolaan sampah masyarakat Kampung Cijagra, dimana 60% masyarakat memberi feedback “setuju” dan sisanya “sangat setuju”.Kata kunci: Sampah, IoT, Monitoring, Banjir, Sungai

Full-field spectroscopic measurement of the X-ray beam from a multilayer monochromator using a hyperspectral X-ray camera

Multilayer monochromator devices are commonly used at (imaging) beamlines of synchrotron facilities to shape the X-ray beam to relatively small bandwidth and high intensity. However, stripe artefacts are often observed and can deteriorate the image quality. Although the intensity distribution of these artefacts has been described in the literature, their spectral distribution is currently unknown. To assess the spatio-spectral properties of the monochromated X-ray beam, the direct beam has been measured for the first time using a hyperspectral X-ray detector. The results show a large number of spectral features with different spatial distributions for a [Ru, B4C] strip monochromator, associated primarily with the higher-order harmonics of the undulator and monochromator. It is found that their relative contributions are sufficiently low to avoid an influence on the imaging data. The [V, B4C] strip suppresses these high-order harmonics even more than the former, yet at the cost of reduced efficiency.