232 research outputs found
On the spatial and temporal coherence of wireless vehicular short range channels
No full textWe consider spatial and temporal coherence of the vehicle–to–vehicle (V2V) wireless communication channel with focus on a suburban residential highway. The dominant reflectors in such an environment are vehicles passing in the adjacent lane and houses
along the road. Instead of treating the reflectors as point targets, the V2V short range propagation environment requires partitioning of the illuminated reflector side into
sufficiently small tiles. The channel transfer function is obtained as a superposition of specular reflections from the tiles, the line–of–sight (LOS) component, and the ground reflection. The tile size is selected to ensure that the ratio of the tile area to the tile–to–receiver distance satisfies the far field conditions. The reflected power is described by the tile radar cross section (RCS). The bistatic physical optics RCS model is adapted to account for the tile’s orientation with respect to the ray geometry. We apply the superposition model to the numerical analysis of two general scenarios
for a 22MHz channel in the 2.4GHz band. The first scenario considers a single vehicle reflector passing in the lane adjacent to the V2V communication pair. Both the vector network analyzer (VNA) experiments and the tiling model analysis illustrate that repositioning of the reflector, the transmitter, or the receiver by a few centimeters results in change of the signal power by several decibels. The second scenario analysis characterizes the channel coherence statistics for the
suburban residential highway. We consider the V2V single lane LOS and non–LOS geometries, where in the latter the receiver is shadowed by a large vehicle. The reflectors are both houses and vehicles passing in the opposite direction. The measure of channel coherence is the normalized spatial covariance calculated by correlating transfer functions corresponding to feasible receiver position pairs and performing spatial smoothing. The area of feasible receiver positions is divided into contiguous squares
whose size ensures wide sense quasi–stationarity within the square. Irrespective of direction the correlation remains high and a typical sedan roof usually does not provide sufficient spacing to obtain average inter–antenna correlation lower than 0.5. The upper bound on coherence time extends over the transmission time of multiple packets for systems in the considered band, and does not allow for usable time diversity.Ph.D.Includes bibliographical referencesIncludes vitaby Haris Krem
Explosive indentation study of B4C-TiAlx composites fabricated by the dipping exothermic reaction process
No full textThe aim of this study is to fabricate a high volume fraction B4C-reinforced intermetallic matrix composite by the dipping exothermic reaction process and investigate the shock impact damage response of composites by explosive indentation experiment. It has been shown that the final microstructure of the dipping exothermic reaction process-fabricated composite can be tailored by treatment of the constituent powders and post heat treatment. The hardness and impact damage resistance of the fabricated composites were evaluated.This work is supported by grants (No. N62649-03-0007) from AROFE(US Army
Research Office Far-East). The author thanks Drs. J. W. McCauley of ARL, Sean Yu and
R. Olesinskiof AROFE
Increasing the Performance of Passive Communication with Ambient Light
No full textMost wireless communication technologies have been using the Radio Frequency (RF) spectrum for decades. Due to the popularity of the Internet of Things (IoT), the RF spectrum has started to become densely populated. Researchers have begun to explore other bands of the electromagnetic spectrum that can be utilized as a communication media. One of the promising choices is the visible light spectrum.Visible Light Communication (VLC) refers to the wireless communication technology that utilizes the visible light spectrum. This spectrum is thousands of times wider than the Radio Frequency (RF) spectrum and is license-free. In VLC, data is transmitted by turning a light source on and off. However, not every light source can be controlled. Passive light sources such as the sun provide an immense amount of light that can be used for wireless communication if we can develop ways to modulate them. One of the researches that use ambient light to create a wireless link is LuxLink. LuxLink uses liquid crystal shutters to control passive light sources and provides low energy, reliable, and flicker-free (safe) communication. This thesis addresses several problems that the current LuxLink system has.We present LuxLink+, an extension of LuxLink that provides two main improvements. Firstly, the data rate of the system is relatively low (80~bps). To increase the data rate, we provide a thorough analysis of the system’s bandwidth. Afterward, we modify the modulation technique, which increases the data rate to 1000~bps at a range of 1.5~m.Secondly, the system has a static data rate, which means that the system cannot adapt its data rate to changes in the environment. We implement a rate adaptation algorithm that can change its data rate accordingly. LuxLink+ improves the average throughput of the system by up to 85 percent compared to LuxLink.Electrical Engineering | Embedded System
READINESS, SKILLS, AND ENGAGEMENT OF ELEMENTARY SCHOOL STUDENTS IN INFORMATION AND COMMUNICATION TECHNOLOGY-BASED SCIENCE LEARNING IN BOYOLALI REGENCY
No full textPenelitian ini bertujuan untuk menganalisis kesiapan, keterampilan, dan keterlibatan peserta didik Sekolah Dasar dalam pembelajaran Ilmu Pengetahuan Alam dan Sosial (IPAS) berbasis Teknologi Informasi dan Komunikasi (TIK) di Kabupaten Boyolali. Menggunakan pendekatan mixed methods, penelitian ini menggabungkan data kuantitatif dan kualitatif untuk memperoleh gambaran yang komprehensif mengenai aspek teknis, kognitif, afektif, dan sosial peserta didik. Hasil penelitian menunjukkan bahwa kesiapan teknis peserta didik berada pada kategori cukup baik, terutama dalam penggunaan ponsel sebagai media pembelajaran, meskipun masih terdapat kesenjangan akses perangkat yang menimbulkan perbedaan keterampilan operasional. Dari aspek kognitif dan afektif, pemanfaatan TIK terbukti mampu meningkatkan pemahaman, minat, dan motivasi belajar peserta didik, namun tantangan seperti distraksi digital dan gangguan teknis masih menghambat keberlanjutan proses belajar. Sementara itu, kesiapan sosial peserta didik mulai terbentuk melalui interaksi dan kolaborasi digital, meskipun masih diperlukan pembinaan intensif mengenai etika berkomunikasi di ruang daring. Temuan ini menegaskan pentingnya peran kolaboratif guru, orang tua, dan sekolah dalam memastikan pemanfaatan TIK secara efektif, beretika, dan berkelanjutan. Penelitian ini diharapkan dapat memberikan kontribusi bagi pengembangan strategi pembelajaran IPAS berbasis TIK yang lebih adaptif dan merata di lingkungan pendidikan dasar.This study aims to analyze the readiness, skills, and engagement of elementary school students in Technology and Information Communication (ICT)-based Science and Social Studies (IPAS) learning in Boyolali Regency. Using a mixed methods approach, this study integrates quantitative and qualitative data to obtain a comprehensive overview of students’ technical, cognitive, affective, and social aspects. The findings indicate that students’ technical readiness is in the “adequate” category, particularly in the use of mobile phones as learning media, although gaps in device accessibility still create differences in operational skills. From cognitive and affective perspectives, the use of ICT has been shown to enhance students’ understanding, interest, and learning motivation; however, challenges such as digital distractions and technical issues continue to hinder learning consistency. Meanwhile, students’ social readiness has begun to develop through digital interaction and collaboration, although intensive guidance on online communication ethics is still required. These findings highlight the crucial collaborative roles of teachers, parents, and schools in ensuring effective, ethical, and sustainable use of ICT in learning. This study is expected to contribute to the development of more adaptive and equitable ICT-based IPAS learning strategies in elementary education settings
Performance investigation of an integrated wind energy system for co-generation of power and hydrogen
No full textIn this paper, a wind turbine energy system is integrated with a hydrogen fuel cell and proton exchange membrane electrolyzer to provide electricity and heat to a community of households. Different cases for varying wind speeds are taken into consideration. Wind turbines meet the electricity demand when there is sufficient wind speed available. During high wind speeds, the excess electricity generated is supplied to the electrolyzer to produce hydrogen which is stored in a storage tank. It is later utilized in the fuel cell to provide electricity during periods of low wind speeds to overcome the shortage of electricity supply. The fuel cell operates during high demand conditions and provides electricity and heat for the residential application. The overall efficiency of the system is calculated at different wind speeds. The overall energy and exergy efficiencies at a wind speed 5 m/s are then found to be 20.2% and 21.2% respectively
Multigeneration system exergy analysis and thermal management of an industrial glassmaking process linked with a Cu–Cl cycle for hydrogen production
No full textA multigeneration system for hydrogen production linked with a glassmaking process via thermal management is examined in this study. The exhaust gas is interconnected with a Rankine cycle and the copper-chlorine (Cu–Cl) cycle for hydrogen production. The present system consists of a steam Rankine cycle, Cu–Cl cycle with multistage compression, double-stage organic Rankine cycle, and multi-effect desalination system. A Cu–Cl cycle based on the four-step model is employed with the proposed system. The useful system outputs are electricity, hydrogen, and fresh water. The simulation software packages utilized in the analysis and modeling are Engineering Equation Solver and Aspen Plus. The energy efficiency of the overall system is 36.5% while 38.1% is the exergy efficiency. The parametric studies are conducted to investigate the system performance. In addition, the effects of exhaust gas variables, such as flow rate, temperature, and pressure are examined to investigate the system performance
Leadership strategies for embedding sustainability and resilience in organizations with an emphasis on sustainable energy
No full textEfficient strategies to embedding sustainability in an organization are frequently linked to effective leadership. By design, changes in direction within an organization may lead to alterations in commitment or perceived significance of sustainability in organizations. While some organizational leaders are interested in embedding sustainability within a structure, other leaders believe in leaving the legacy behind and permanently influencing sustainability efforts. To confirm or dispel the underscored notion of the importance of leadership in embedding sustainability in organizations, a qualitative methodology approach to interviews, document analyses, and literature review is utilized. The research inquiry includes in-person interviews with top city staff and elected officials in a large Midwestern city and a review of the internal documents and reports. The end goal of the research is an examination of the role both elected and appointed officials have in embedding sustainability within cities, and whether a change in leadership may have an impact on continuity of sustainability implementation and
long-term viability of such policies. The paper focuses on the application of sustainable energy policies within a local government organizational structure as a mean of constructing a better understanding of leadership on sustainability implementation and embedment. While the further inquiry is needed, the research points out that an active partnership between city managers, administrators, and elected officials must be in place to support integrating sustainability from within and that sustainability thrives where exhaustive leadership support such
initiatives and efforts.Journal ArticleFinal article publishe
Measuring the Sustainability Impact in Local Governments Using the Quadruple Bottom Line
No full textSustainability is utilized by cities to enable a multifaceted, cross-sectoral approach for the betterment of communities and operational efficiency of organizations. Using a case study of the medium size local government in the Midwest and the city’s application of sustainability planning, this article focuses on a development of an expanded definition of the bottom line and a nascent approach to measuring and tracking sustainability-related efforts. The research provides an overview of measuring sustainability adopted by this particular city, using the target-specific,extended quadruple bottom line approach. The method attempts to address economic vitality, environmental quality, social equity, and governmental accountability through governance. The use of the quadruple bottom line to measure sustainability is linked to its annual budget planning and investments in transformation-related initiatives. While such an approach to measuring sustainability progress is unique in the United States, a number of cities in Australia have also adopted the quadruple bottom line approach to measure sustainability. Lessons in reporting sustainability efforts using the quadruple bottom line, in the context of an efficient and effective service delivery, can be applied to other local governments.Journal ArticleFinal article publishe
Ljiljana Dobrovšak, Jews in Srijem, from immigration to the Holocaust, State Archives in Vukovar, Special Editions III., Vukovar, 2017, 376 pages.
No full textSredinom 2017. godine, Državni arhiv u Vukovaru objavio je knjigu o Židovima u Srijemu povjesničarke dr.sc. Ljiljane Dobrovšak. Autorica knjige Ljiljana Dobrovšak, viša je znanstvena suradnica sa Instituta društvenih znanosti „Ivo Pilar” iz Zagreba koja od završetka studija povijesti istražuje povijest Židova u Hrvatskoj od kraja 18. stoljeća pa sve do današnjih dana. Nakon što je 2013. objavila knjigu o Židovima u Osijeku, nastavila je istraživati povijest slavonskih i srijemskih židovskih zajednica, pa je kao rezultat njezinih dugogodišnjih istraživanja objavljena ova sveobuhvatna monografija. Knjiga „Židovi u Srijemu, Od doseljenja do Holokausta” na 376 stranica obrađuje povijest srijemskih židovskih zajednica na području danas srpskog i hrvatskog dijela Srijema (nekadašnje Srijemske županije). Iako autorica piše o židovskim zajednicama u cijelom Srijemu (Zemun, Petrovaradin, Šid, Ruma, Erdevik i Srijemska Mitrovica), te daje pregled njihove povijesti, osobiti naglasak stavila je na povijest Židova u Vukovaru i Iloku. Autorica se pri pisanju ove monografije koristila arhivskim izvorima kao i objavljenim i neobjavljenim znanstvenim i drugim dijelima, koje je znanstveno-analitičkom metodom analizirala, o čemu svjedoči bogata bibliografija na kraju knjige.In the middle of 2017, the State Archives in Vukovar published a book about the Jews in Srijem by the historian, PhD Ljiljana Dobrovšak. The author of the book, Ljiljana Dobrovšak, is a senior researcher at the "Ivo Pilar" Institute of Social Sciences from Zagreb, who has been researching the history of Jews in Croatia from the end of the 18th century until the present day since completing her studies in history. After publishing a book about the Jews in Osijek in 2013, she continued researching the history of the Slavonian and Srijem Jewish communities, and as a result of her long-term research, this comprehensive monograph was published. The 376-page book "Jews in Srijem, From Immigration to the Holocaust" deals with the history of the Jewish communities of Srijem in the area of today's Serbian and Croatian parts of Srijem (the former Srijem County). Although the author writes about the Jewish communities in the whole of Srijem (Zemun, Petrovaradin, Šid, Ruma, Erdevik and Srijemska Mitrovica) and gives an overview of their history, she places particular emphasis on the history of the Jews in Vukovar and Ilok. When writing this monograph, the author used archival sources as well as published and unpublished scientific and other works, which she analysed using the scientific-analytical method, as evidenced by the rich bibliography at the end of the book.Tema broja "Holokaust i restitucija u bivšoj Jugoslaviji: pravni i istorijski izazovi" (the issue's theme is "Holocaust and Restitution in the Former Yugoslavia: Legal and Historical Challenges")
Personality of the Main Character Jemima in the Novel God for Jemima by Indah Hanaco Psychological Study of Literary
No full textLiterary works are imaginative results or creations conveyed communicatively by the author which contain the aesthetics of the life of the people who created them. Literary works are created by writers to be enjoyed, understood and utilized by society. A novel is a long prose essay that contains a series of stories about a person's life and the people around him, highlighting the character and nature of each actor. Generally, stories in novels begin with the most important incident or event experienced by the character in the story which will later change the fate of his life. Thus, the characters and characters will develop until they experience a change in fate or experience an important event.
In general, the definition of a character is an individual created by the author who experiences the events in the story. Psychology is a science that researches and studies behavior or activities which are seen as manifestations of human psychological life. In general, literary psychology is a science that studies humans from the inside. Literary psychology was born as a type of literary study which is used to read and interpret literary works, authors of literary works and their readers using various concepts and theoretical frameworks that exist in psychology. Psychoanalysis is a scientific discipline that studies human functioning and development. In this research, the author uses two theories, namely Hippocrates' theory of personality types which is divided into 4 parts, namely Choleric, Melancholic, Phlegmatic and Sanguine, then Sigmund Freud's psychoanalytic theory which is divided into 4 parts, namely Id, Ego and Superego. This research aims to describe the type of personality possessed by the character "Jemima" in the novel God for Jemima by Indah Hanaco. From the results of this research, it can be concluded what type of personality the character "Jemima" has and its relationship with the personality system in the aspect of Sigmund Freud's psychoanalysis contained in the novel God for Jemima by Indah Hanaco.66 PagesSkripsi Sarjan
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