bluuebunny/crossref_metadata_2025 huggingface dataset:
Align, then memorise: the dynamics of learning with feedback alignment*
Authors: Refinetti Maria , d’Ascoli Stéphane , Ohana Ruben , Goldt Sebastian
Published: November 2022

Direct feedback alignment (DFA) is emerging as an efficient and biologically plausible alternative to backpropagation for training deep neural networks. Despite relying on random feedback weights for the backward pass, DFA successfully trains state-of-the-art models such as transformers. On the other hand, it notoriously fails to train convolutional networks. An understanding of the inner workings of DFA to explain these diverging results remains elusive. Here, we propose a theory of feedback alignment algorithms. We first show that learning in shallow networks proceeds in two steps: an alignment phase, where the model adapts its weights to align the approximate gradient with the true gradient of the loss function, is followed by a memorisation phase, where the model focuses on fitting the data. This two-step process has a degeneracy breaking effect: out of all the low-loss solutions in the landscape, a network trained with DFA naturally converges to the solution which maximises gradient alignment. We also identify a key quantity underlying alignment in deep linear networks: the conditioning of the alignment matrices. The latter enables a detailed understanding of the impact of data structure on alignment, and suggests a simple explanation for the well-known failure of DFA to train convolutional neural networks. Numerical experiments on MNIST and CIFAR10 clearly demonstrate degeneracy breaking in deep non-linear networks and show that the align-then-memorize process occurs sequentially from the bottom layers of the network to the top.
Approximate message passing with spectral initialization for generalized linear models*
Authors: Mondelli Marco , Venkataramanan Ramji
Published: November 2022

We consider the problem of estimating a signal from measurements obtained via a generalized linear model. We focus on estimators based on approximate message passing (AMP), a family of iterative algorithms with many appealing features: the performance of AMP in the high-dimensional limit can be succinctly characterized under suitable model assumptions; AMP can also be tailored to the empirical distribution of the signal entries, and for a wide class of estimation problems, AMP is conjectured to be optimal among all polynomial-time algorithms. However, a major issue of AMP is that in many models (such as phase retrieval), it requires an initialization correlated with the ground-truth signal and independent from the measurement matrix. Assuming that such an initialization is available is typically not realistic. In this paper, we solve this problem by proposing an AMP algorithm initialized with a spectral estimator. With such an initialization, the standard AMP analysis fails since the spectral estimator depends in a complicated way on the design matrix. Our main contribution is a rigorous characterization of the performance of AMP with spectral initialization in the high-dimensional limit. The key technical idea is to define and analyze a two-phase artificial AMP algorithm that first produces the spectral estimator, and then closely approximates the iterates of the true AMP. We also provide numerical results that demonstrate the validity of the proposed approach.
Equilibrium and non-equilibrium regimes in the learning of restricted Boltzmann machines*
Authors: Decelle Aurélien , Furtlehner Cyril , Seoane Beatriz
Published: November 2022

Training restricted Boltzmann machines (RBMs) have been challenging for a long time due to the difficulty of precisely computing the log-likelihood gradient. Over the past few decades, many works have proposed more or less successful training recipes but without studying the crucial quantity of the problem: the mixing time, i.e. the number of Monte Carlo iterations needed to sample new configurations from a model. In this work, we show that this mixing time plays a crucial role in the dynamics and stability of the trained model, and that RBMs operate in two well-defined regimes, namely equilibrium and out-of-equilibrium, depending on the interplay between this mixing time of the model and the number of steps, k, used to approximate the gradient. We further show empirically that this mixing time increases with the learning, which often implies a transition from one regime to another as soon as k becomes smaller than this time. In particular, we show that using the popular k (persistent) contrastive divergence approaches, with k small, the dynamics of the learned model are extremely slow and often dominated by strong out-of-equilibrium effects. On the contrary, RBMs trained in equilibrium display faster dynamics, and a smooth convergence to dataset-like configurations during the sampling. Finally, we discuss how to exploit in practice both regimes depending on the task one aims to fulfill: (i) short k can be used to generate convincing samples in short learning times, (ii) large k (or increasingly large) is needed to learn the correct equilibrium distribution of the RBM. Finally, the existence of these two operational regimes seems to be a general property of energy based models trained via likelihood maximization.
Encounter-based model of a run-and-tumble particle
Authors: Bressloff Paul C
Published: November 2022

In this paper we extend the encounter-based model of diffusion-mediated surface absorption to the case of an unbiased run-and-tumble particle (RTP) confined to a finite interval [0, L] and switching between two constant velocity states ±v at a rate α. The encounter-based formalism is motivated by the observation that various surface-based reactions are better modeled in terms of a reactivity that is a function of the amount of time that a particle spends in a neighborhood of an absorbing surface, which is specified by a functional known as the boundary local time. The effects of surface reactions are taken into account by identifying the first passage time (FPT) for absorption with the event that the local time crosses some random threshold

ℓ

^

. In the case of a Brownian particle, the local time ℓ(t) is a continuous non-decreasing function of the time t. Taking

Ψ

(

ℓ

)

≡
P

[

ℓ

^

>
ℓ

]

to be an exponential distribution,

Ψ

[

ℓ

]

=

e

−

κ

0

ℓ

, is equivalent to imposing a Robin boundary condition with a constant rate of absorption κ
0. One major difference in the encounter-based model of an RTP is that the boundary local time ℓ(t) is a now a discrete random variable that counts the number of collisions of the RTP with the boundary. Given this modification, we show that in the case of a geometric distribution Ψ(ℓ) = z

ℓ
, z = 1/(1 + κ
0/v), we recover the RTP analog of the Robin boundary condition. This allows us to solve the boundary value problem (BVP) for the joint probability density for particle position and the local time, and thus incorporate more general models of absorption based on non-geometric distributions Ψ(ℓ). We illustrate the theory by calculating the mean FPT (MFPT) for absorption at x = L given a totally reflecting boundary at x = 0. We also determine the splitting probability for absorption at x = L when the boundary at x = 0 is totally absorbing.
Development of optical sensor system and hardware base frame for checking the light and radiation fields of a linear accelerator
Authors: Lee B. , Kang S.W. , Kim J.Y. , Lee J. , Kim H.J. , Kim W.C. , Song C. , Eom K.Y. , Kim I.A. , Kim J.S. , Chung J.B.
Published: November 2022

This study aims to quantitatively evaluate the light and radiation fields of a linear accelerator by developing an optical sensor quality assurance (QA) system using a cadmium sulfide (CdS) photodetector cell and a hardware base frame manufactured in-house. The CdS photodetector cell used as the optical sensor has a size of 3.4 × 4.1 mm2, can measure up to 100 lux of light, and has a response time of approximately 20 to 30 ms. To check the alignment of the light field, it was manufactured with a CdS cell optical fiber holder, and the microcontroller board and control module were configured to scan the light field profile. Additionally, for accurate operation of the sensor, it was programmed using the integrated development environment (IDE) sketch. The alignment check of the radiation field was analyzed using the image data measured with electronic portal imaging device (EPID) using the manufactured hardware base frame. An analysis program written in MATLAB was used to evaluate the alignment of the radiation field. For symmetric fields measured using the optical sensor QA system, the full width at half maximum (FWHM) values of crossline (X) and inline (Y) profiles were 100.391 mm and 98.725 mm, respectively, for a field size of 100 × 100 mm2, and 199.093 mm and 198.886 mm, respectively, for a field size of 200 × 200 mm2. The X and Y FWHM values measured by the sensor system for the light fields were within 1 mm of the field size of the visual inspection. In addition, the FWHM value of the asymmetric radiation field measured using the fabricated frame and EPID was measured from the center bearing ball of the field to the bearing ball in each field of the four directions in the EPID image, and when the X1, X2, Y1, and Y2 jaws were opened by 50 mm, FWHM values were 50.120 mm, 50.240 mm, 48.860 mm, and 49.870 mm, respectively. The corresponding values were 99.520 mm, 99.570 mm, 99.010 mm, and 99.880 mm when the jaw fields were opened by 100 mm. The optical sensor system and hardware base frame developed in this study demonstrated the ability to evaluate both light and radiation fields more simply and quantitatively when compared to the conventional QA process. This QA system will provide medical physicists with more reliable QA results than the conventional QA method that uses graph paper and film.
Annelid-inspired high-elongation origami robot using partial material removal
Authors: Wei Xianhe , Zhao Yanzhi , Fan Zhengwei , Guo Zhifeng , Han Zhen , Shan Yu , Liu Zhixin
Published: November 2022

Existing soft robots face challenges given the need for an improved flexible robot elongation rate, bending angle and movement flexibility in space target acquisition, disaster search and rescue, unknown environment detection and other fields. Yoshimura tubular origami shows good applied performance with regard to the axial elongation ratio. However, due to the characteristics of nonrigid folding and a negative Poisson’s ratio, the axial elongation length and bending angle of the Yoshimura tubular origami mechanism are limited. Annelids show highly flexible body movement. By analyzing the main factors limiting the axial elongation rate of the Yoshimura tubular origami mechanism and imitating the morphological characteristics and motion mechanism of annelid somite joints, we proposed a method to achieve high flexibility and large angle bending of a tubular origami mechanism based on local material removal and macroscopic elimination of the negative Poisson’s ratio. Combined with a Ni–Ti memory alloy wire segmented driving scheme based on force constraints and geometric constraints a continuous origami robot is designed. The optimal cutting amount of the origami mechanism is determined by experiments, and the maximum elongation ratio and bending angle of the origami mechanism reach 2.5 and 3 times those before material removal, respectively. The paper folding module unit was solved in a kinematic analysis workspace. Finally, a prototype was used to verify the performance and demonstrate the application potential of the robot in an unstructured rescue scene.
Bio-inspired conductive adhesive based on calcium-free alginate hydrogels for bioelectronic interfaces
Authors: Perkucin Ivana , Lau Kylie S K , Morshead Cindi M , Naguib Hani E
Published: November 2022

Electrode impedance is one of the greatest challenges facing neural interfacing medical devices and the use of electrical stimulation-based therapies in the fields of neurology and regenerative medicine. Maximizing contact between electronics and tissue would allow for more accurate recordings of neural activity and to stimulate with less power in implantable devices as electric signals could be more precisely transferred by a stable interfacial area. Neural environments, inherently wet and ion-rich, present a unique challenge for traditional conductive adhesives. As such, we look to marine mussels that use a 3,4-dihydroxyphenyl-L-analine (DOPA)-containing proteinaceous excretion to adhere to a variety of substrates for inspiration. By functionalizing alginate, which is an abundantly available natural polymer, with the catechol residues DOPA contains, we developed a hydrogel-based matrix to which carbon-based nanofiller was added to render it conductive. The synthesized product had adhesive energy within the range of previously reported mussel-based polymers, good electrical properties and was not cytotoxic to brain derived neural precursor cells.
Contrasting ecosystem constraints on seasonal terrestrial CO2 and mean surface air temperature causality projections by the end of the 21st century
Authors: Hagan Daniel F T , Dolman Han A J , Wang Guojie , Sian Kenny T C Lim Kam , Yang Kun , Ullah Waheed , Shen Runping
Published: November 2022

Two centuries of studies have demonstrated the importance of understanding the interaction between air temperature and carbon dioxide (CO2) emissions, which can impact the climate system and human life in various ways, and across different timescales. While historical interactions have been consistently studied, the nature of future interactions and the impacts of confounding factors still require more investigation in keeping with the continuous updates of climate projections to the end of the 21st century. Phase 6 of the Coupled Model Intercomparison Project (CMIP6), like its earlier projects, provides ScenarioMIP multi-model projections to assess the climate under different radiative forcings ranging from a low-end (SSP1–2.6) to a high-end (SSP5–8.5) pathway. In this study, we analyze the localized causal structure of CO2, and near-surface mean air temperature (meanT) interaction for four scenarios from three CMIP6 models using a rigorous multivariate information flow (IF) causality, which can separate the cause from the effect within the interaction (CO2–meanT and meanT–CO2) by measuring the rate of IF between parameters. First, we obtain patterns of the CO2 and meanT causal structures over space and time. We found a contrasting emission-based impact of soil moisture (SM) and vegetation (leaf area index (LAI)) changes on the meanT–CO2 causal patterns. That is, SM influenced CO2 sink regions in SSP1–2.6 and source regions in SSP5–8.5, and vice versa found for LAI influences. On the other hand, they function similarly to constrain the future CO2 impact on meanT. These findings are essential for improving long-term predictability where climate models might be limited.
Excess deaths associated with long-term exposure to ambient NO2 in China
Authors: Qi Ling , Fu Anqi , Duan Xiaoli
Published: November 2022

World Health Organization updated the target of annual mean NO2 from 40 μg m−3 to 10 μg m−3 in 2021 based on new evidences that showed statistically independent effects of long-term exposure to ambient NO2 and mortality. We estimate the excess deaths associated with long-term exposure to ambient NO2 (DAAN) from non-accidental disease (NAD), cardiovascular disease (CVD) and respiratory disease (RD) in China in 2013–2020 using a counterfactual analytic framework adopted by Global Burden Disease. We use relative risk (RR) values based on a meta-analysis, and assume a linear concentration-response (C-R) function and a threshold value of 10 μg m−3. DAAN from NAD vary in 279 (95% Cl: 189–366) to 339 (95% Cl: 231–442) thousand in 2013–2020, comparable to excess deaths attributed to long-term exposure to ambient O3 in China. DAAN from NAD changes by −43%–+220% using different RR values, C-R function shapes, and threshold values. DAAN from RD reduces while those from CVD increases significantly in 2013–2020. DAAN from RD account for ∼10% of total DAAN. We found that the reduction of NO2 concentration and baseline mortality of NAD offsets the adverse effects of population growth and aging in 2013–2017. In 2017–2020, the contribution from air pollution reduction surpasses the adverse effects of population growth and aging in most regions. We suggest that continuing the reduction rate of NO2 emissions in 2013–2020 would offset the effects of population growth and aging in 2020–2030. Faster reduction of NO2 sources is required to reduce DAAN in Liaoning, Shanxi, Shanghai, and Anhui, where DAAN from NAD, CVD and RD increased in 2013–2020. Our results should be interpreted with caution because the causality support of long-term exposure to ambient NO2 on mortality from toxicological studies is not firm yet, and NO2 is possibly just a marker of traffic-related pollutants.
Mid-summer snow-free albedo across the Arctic tundra was mostly stable or increased over the past two decades
Authors: Plekhanova Elena , Kim Jin-Soo , Oehri Jacqueline , Erb Angela , Schaaf Crystal , Schaepman-Strub Gabriela
Published: November 2022

Arctic vegetation changes, such as increasing shrub-cover, are expected to accelerate climate warming through increased absorption of incoming radiation and corresponding decrease in summer shortwave albedo. Here we analyze mid-summer shortwave land-surface albedo and its change across the pan-Arctic region based on MODerate resolution Imaging Spectroradiometer satellite observations over the past two decades (2000–2021). In contrast to expectations, we show that terrestrial mid-summer shortwave albedo has not significantly changed in 82% of the pan-Arctic region, while 14% show an increase and 4% a decrease. The total median significant change was 0.014 over the past 22 years. By analyzing the visible and near-/shortwave-infrared range separately, we demonstrate that the slight increase arises from an albedo increase in the near-/shortwave infrared domain while being partly compensated by a decrease in visible albedo. A similar response was found across different tundra vegetation types. We argue that this increase in reflectance is typical with increasing biomass as a result of increased multiple reflection in the canopy. However, CMIP6 global land surface model albedo predictions showed the opposite sign and different spatial patterns of snow-free summer albedo change compared to satellite-derived results. We suggest that a more sophisticated vegetation parametrization might reduce this discrepancy, and provide albedo estimates per vegetation type.
Origin of the spontaneous oscillations in a simplified coagulation-fragmentation system driven by a source
Authors: Fortin Jean-Yves
Published: November 2022

We consider a system of aggregated clusters of particles, subjected to coagulation and fragmentation processes with mass dependent rates. Each monomer particle can aggregate with larger clusters, and each cluster can fragment into individual monomers with a rate directly proportional to the aggregation rate. The dynamics of the cluster densities is governed by a set of Smoluchowski equations, and we consider the addition of a source of monomers at constant rate. The whole dynamics can be reduced to solving a unique non-linear differential equation which displays self-oscillations in a specific range of parameters, and for a number of distinct clusters in the system large enough. This collective phenomenon is due to the presence of a fluctuating damping coefficient and is closely related to the Liénard self-oscillation mechanism observed in a more general class of physical systems such as the van der Pol oscillator.
Algebraic area enumeration for open lattice walks
Authors: Ouvry Stéphane , Polychronakos Alexios P
Published: November 2022

We calculate the number of open walks of fixed length and algebraic area on a square planar lattice by an extension of the operator method used for the enumeration of closed walks. The open walk area is defined by closing the walks with a straight line across their endpoints and can assume half-integer values in lattice cell units. We also derive the length and area counting of walks with endpoints on specific straight lines and outline an approach for dealing with walks with fully fixed endpoints.
Effects of reduced measurements independence on self-testing
Authors: Li Xinhui , Wang Yukun , Han Yunguang , Zhu Shi-Ning
Published: November 2022

Self-testing, which refers to device independent characterization of the state and the measurement, has been intensively studied in quantum information theory. One of the implicit assumptions in self-testing theorem is, measurement settings should be chosen randomly and independently by each party. The relaxation of this assumption potentially gives untrusted device providers the power to control the device with no quantum feature, even fake the quantum behavior by using the classical strategies within the device. In this paper, we analyze the effects of the reduced measurements independence on self-testing two-qubit entangled states based on the violation of Bell inequalities. By assuming adversary’s capabilities, we show to achieve the maximum CHSH violation in this case, four different state-measurements preparations should be provided. Without run information one could not really self-test the underlying system in each run anymore, but it must be equal with one of four entangled systems up to local unitaries.
Bundle theoretic descriptions of massive single-particle state spaces; with a view toward relativistic quantum information theory
Authors: Lee Heon
Published: November 2022

Relativistic Quantum Information Theory (RQI) is a flourishing research area of physics, yet, there has been no systematic mathematical treatment of the field. In this paper, we suggest bundle theoretic descriptions of massive single-particle state spaces, which are basic building blocks of RQI. In the language of bundle theory, one can construct a vector bundle over the set of all possible motion states of a massive particle, in whose fibers the moving particle’s internal quantum state as perceived by a fixed inertial observer is encoded. A link between the usual Hilbert space description is provided by a generalized induced representation construction on the L
2-section space of the bundle. The aim of this paper is two-fold. One is to communicate the basic ideas of RQI to mathematicians and the other is to suggest an improved formalism for single-particle state spaces that encompasses all known massive particles including those which have never been dealt with in the RQI literature. Some of the theoretical implications of the formalism will be explored at the end of the paper.
Calculation model of spaciousness in rooms with windows-Experimental procedure for spaciousness evaluation using VR-
Authors: Nishihara S , Okada M , Miyake H , Yamaguchi H , Yoshizawa N
Published: November 2022

Spaciousness is an important psychophysical value of space which has impacts on building occupants’ satisfaction and wellness. Previous research revealed through subjective experiments in spaces without windows that spaciousness is affected not only by the physical volume of space but also by lighting environment, and the effect can be estimated with a calculation model with average luminance and “dark-part-reduced visible volume”. The purpose of this study is to expand the scope of the calculation model to spaces with windows through subjective experiment, and for that, to improve the experimental procedure for steady comparison of various spaces in size avoiding stimulus range bias. We determined “typical standard conditions” as three sizes of simple rectangular spaces with uniform general lighting to cover experiments which use comparative condition spaces in visible volume of 10m3-2490m3. These are created with Virtual Reality to enable subjects to compare spaces apart from each other in reality, and to reduce the cost of preparing various spaces. We conducted a subjective experiment with this improved procedure in a room with windows and revealed that the accuracy of calculation model can be improved by additionally considering configuration factors of windows and applying different weighting factors to the volume corresponding to the windows.
Bio-mimetic Approaches to Kinetic Facades: A Design Proposal for a Light-Responsive Facade Module.
Authors: Scavée Anastasiia , Triantafyllidis Georgios , Palamas George
Published: November 2022

Facades are important for controlling light entering a building and ensuring optimal conditions for occupants. But light can also cause discomfort, such as glare and overheating. Natural light changes with the time of day, the weather, and the season. Creating a responsive structure can enhance the visual quality and energy efficiency. Because of their properties, kinetic facades can react to various stimuli, such as heat and sunlight. In this paper, we discuss bio-mimetic approaches to kinetic facades and how they can be used to develop a design proposal for the light-responsive facade module. Motors drive most kinetic facades, which adds to the maintenance costs, thus,shape memory alloys (SMAs) are investigated as actuators. Facades should be visually appealing and reflect the bio-mimetic concept of the project while allowing natural light to pass through. The results show that the suggested solutions are both feasible and aesthetically pleasing, thus comparable to traditional kinetic facade workflows. In conclusion, if bio-mimicry is to be used in large-scale construction, it is imperative that it is examined for the effects of different environmental conditions on bio-mimetic patterns.
Relationship between the gaze point movement and spatial brightness
Authors: Kage H , Harimoto K , Ishiwata Y , Yoshizawa N
Published: November 2022

This study aims to verify the relationship between the spatial brightness evaluation and average luminance on a moving gaze point tracking by targeting offices with different luminance distributions. Subjects wearing eye-tracking devices evaluate the spatial brightness of the various light environments displayed on a large screen display. In the results, the tendency for gazing at the window is found to be high as compared to the other parts. The average luminance is calculated by integrating the time on the path of the moving gaze point. Furthermore, we analyse the relationship between the average luminance of each part of the light environment on the display and the brightness evaluation value. The average luminance considering the movement of the gaze point at the time of brightness evaluation has higher explanatory power,0.305, for the spatial brightness than the average luminance,0.259, in the entire visual field area. In contrast, the explanatory power of brightness evaluation was not improved drastically, even considering the gazing time and luminance. In future, the relationship between the evaluation of the spatial brightness and the gaze point/gaze time can be analysed by considering the absolute value of the luminance of the window surface and the luminance ratio with the surroundings.
Balanced Brightness Levels: Exploring how lighting affects humans’ experiences of architectural and social urban contexts.
Authors: Hvass Mette , Hansen Ellen Kathrine
Published: November 2022

This paper explores how lighting and darkness influence human experiences of architectural and social public urban contexts in dark hours. Tram stations in Aarhus, Denmark, are used as cases to investigate how brightness levels influence human sensory experience of the local space, the surroundings, co-presence with other people, and the activities performed in a specific context. Furthermore, this paper describes a transdisciplinary process, where methods from natural science, social science and arts/humanities are combined in three pre-analyses and a main field experiment. Lighting is often related to safety while darkness is related to fear. However, the findings from the main field experiment of this project indicate that lower and balanced brightness levels can sharpen our senses and create a relaxed atmosphere. Additionally, lower brightness levels enrich perceptions of and connections with spatial and social surroundings, thereby increasing perceived safety. We argue for context specific field experiments based on pre-analyses and the use of a transdisciplinary process, for drawing nearer to people’s immediate senses when exploring experiences of urban lighting. The ultimate goal of the studies is to inspire to solutions that exploit the architectural and social potential of lighting by lowering and balancing brightness levels, all while reducing energy use and light pollution.
Dynamic Lighting and Natural Ventilation in Patient Rooms at New Psychiatry Bispebjerg
Authors: Volf C , Martiny K , Petersen PM , Corell D D , Dam-Hansen C
Published: November 2022

This paper presents preliminary results of analyzes of the indoor environmental quality (IEQ) in a full scale rotatable 1:1 mockup of a patient room. As initial part of the planning of the indoor environment at a new mental hospital, the project seeks to uncover the natural differences and limitations of the building, caused by the geographical orientation. Examining the outdoor diurnal variations and their effect on the indoor environment, in order to create a balance between on the one hand, daylight and artificial lighting and on the other hand the demand for passive cooling, using natural ventilation. The analysis discuss potential health aspects of daylight and fresh air and proposes a new strategy for dynamic artificial lighting, including natural ventilation to supplement mechanical ventilation. In this article we uncover daylight conditions based on two main parameters; 1) the geographic orientation (N, S, E and W) and 2) the season (summer and winter). Based on the preliminary data and the regional daylight conditions, the article proposes a new way to plan the indoor environmental quality called Lattitude and Orientation Compensated Architectural Lighting (LOCAL).
Artificial light(ing) or electric light(ing)?
Authors: Favero Federico , Besenecker Ute
Published: November 2022

Researchers and designers use the words “artificial” or “electric” to describe lighting products, design, or research related practices, and there appear to be differing opinions about which is the more appropriate term. Generally, there are challenges with a common use of language and vocabulary in interdisciplinary research and this might be also valid for design and research in lighting design across different disciplines. The authors were educated in opposing practices of using “electric” lighting vs “artificial” lighting; this started a discussion and the conceptualization of this article. The paper explores, summarizes and discusses through literature review and a survey the concepts described and conveyed by both terms in different disciplines. Interestingly we could find differences among and between disciplines and professional backgrounds. This might indicate that the education and nomenclature in the field influences the use of terms. We found a tendency to refer to light sources either in terms of the energy used to generate the light, e.g. electric light or gaslight, but also in terms of the effect that it evokes, e.g. candle light is defined natural. Generally, a common lighting glossary could be developed through continuous discussion and studies. As today’s complex questions are discussed in interdisciplinary teams, a common language might promote effective communication and stimulate sustainable solutions.
Urban-Centric Lighting Task Group: Tactical Lighting as an innovation strategy
Authors: Barberá A , Teixidó B
Published: November 2022

The present article describes a perspective on tactical urban lighting and its power as a source for disruption and innovation in the field of urban lighting. It is the result of an applied research that is currently being carried out by a task group formed by technicians, planners, managers and designers from different private companies and public institutions with responsibility and expertise in public lighting and urban planning. The group objective is to explore innovative methods and state of the art technology implementations as a practical application of the evidence-based knowledge in the field of artificial lighting for the sake of health and well-being. The definition of health is extended, as the concept of well-being includes the urban space as an ecosystem. There is also a fundamental source of awareness that comes from social sciences about how the built environment design promotes well-being, or else constitutes a hazard for health. After a definition phase for the methodologies and the technology that would need to be developed, the task group is focused on developing new products and planning a prototype installation on a real playground. A tactical, lightweight intervention in an urban green area in the Metropolitan Region of Barcelona is designed to implement, test, and communicate these innovative methods. Once the experiment is validated, a collaboration with public authorities will allow to introduce innovative perspectives in street lighting. Having received support from local’s regional government innovation programmes, through a competitiveness strengthening initiative, the project is partly funded by the European Commission.
Level of public awareness on climate change in Sabah
Authors: Liwan Audrey , Surianshah Nur Sakina , Surianshah Sarimah , Hwang Josephine Yau Tan
Published: November 2022

This study aims to examine the level of public awareness of climate change issues in Sabah. A total of 300 respondents were involved from several districts in Sabah namely Tawau, Lahad Datu, Sandakan and Kota Kinabalu by using the random sampling method. Data obtained from the questionnaire was analysed by using SPSS software. The result shows that more than 70% of respondents are aware of climate change issues and are concerned with the environment. However, the respondents have lower awareness of green products and government policy related to climate change. Furthermore, the use of green products among respondents is at a moderate level. This indicated the respondents had environmental concerns, but they have lack of knowledge on green consumerism, government policies awareness and green consumerism action. Hence, this study recommends that educational climate change programmes and public awareness campaigns are very crucial to address the low level of green product awareness and practice.
Assessing short term air quality trend in Malaysia based on air pollution index (APi)
Authors: Sentian J , Sayzni M S Nur , Payus C
Published: November 2022

Air Pollution Index (API) is used in Malaysia to determine the daily air quality status, which is calculated based on the daily concentrations of particulate matter (PM10), ground-level ozone (O3), carbon monoxide (CO), sulphur dioxide (SO2) and nitrogen dioxide (NO2). This study presents short-term air quality trends based on API from the 52 air quality monitoring stations nationwide between 2010 and 2016. The air quality data and meteorological conditions were obtained from the Department of Environment and used for the API calculation. The API value is classified into six categories, namely: Good (0-50), Moderate (51-100), Unhealthy (101-200), Very Unhealthy (201-300), Hazardous (301-500), and Emergency (above 500). The coefficient of variation (CV) and Mann-Kendall trend test (MK) were used to assess the API variation and trend in each air quality monitoring station. Between the study periods, the API values were largely varied. Observation at 32 air quality monitoring stations have shown significant but small increasing trends, while 12 stations showed significant decreasing trends, and the remaining 8 stations showed no significant trends. The frequency of exceedance (API>50) was used to assess the percentages of unhealthy days. The analysis has found that air quality in Klang Valley was experiencing the highest number of unhealthy days, while the two Malaysian states in Borneo (Sabah and Sarawak) to be relatively less polluted.
Distribution and Accumulation of Heavy Metals in Marine Sediment from Marudu Bay, Sabah
Authors: Musta Baba , Mamun Dg. Azemah Ag. , Yaccup Rahman , Chee Fuei Pien , Yusop Muhammad Shafie , Gabda Darmesah
Published: November 2022

This study aims to analyse the distribution and factors that control the accumulation of heavy metals in marine sediment from Marudu Bay, Sabah. The sediment samples originated from the various types of rocks, namely ultrabasic rock, basic rock, and chert of ophiolite sequence, and sedimentary rock of the Kudat Formation. A total of 20 sediment core samples were systematically sliced for physico-chemical analysis such as pH value, organic matter (OM), and particle size distribution (PSD). Seven heavy metals are analysed in this research, namely cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), vanadium (V), and zinc (Zn) which is measured using the ICP-OES instrument. Descriptive statistics were used to study the distribution and accumulation of heavy metals from two main stations, namely Sg Karang Station (ST) and Kg Tampakan Station (SK). The results from both stations showed various levels of heavy metal concentration. The average concentration of Mn is between 2.19 mg/kg - 94.77 mg/kg and followed by Cr (0.87 mg/kg - 21.11 mg/kg). For Ni, Zn, Cu, V, and Co, the concentration range were between 0.28 mg/kg - 11.48 mg/kg, 0.94 mg/kg - 6.95 mg/kg, 0.55 mg/kg - 6.01 mg/kg, 0.64 mg/kg - 3.77 mg/kg, and 0.02 mg/kg - 0.85 mg/kg respectively. The result of correlation analysis showed the significant negative relationship between pH with Co, Cr, Ni, Mn, and Zn indicated the increasing concentration in acidic condition. A strong negative correlation between percentage of sand and Co, Cr, Mn, and Ni indicated the decreasing concentration in coarse sediment particle size. However, there was a strong positive correlation between percentage of sand and V due to the association in the carbonate minerals. The Kruskal-Wallis tests showed there were no significant means difference of the percentage of heavy metals based on sample depth and the distance from the shoreline except for V and Mn.
The Conformation and Thermal Characteristic Of Different Species Of Bamboo Cellulose
Authors: Aziz Siti Ayu , Soloi Sabrina , Asrah Hidayati , Idris Juferi , Sarjadi Mohd Sani
Published: November 2022

Bamboo is a fast-growing biomaterial indigenous to Asia and Oceania that is also a high-yielding renewable resource. Bamboo, which has mechanical properties similar to wood, may be treated with currently available methods. The purpose of this study was to determine the characteristics chemical and thermal characteristic of three bamboo species ofSchizostachyum brachycladum, Bambusa vulgaris, andBambusa oldhamii. Bamboo cellulose was extracted chemically via dewaxing, delignification, and mercerization. The bamboo cellulose species employed wereS. brachycladum, B. vulgaris, andB. oldhamii. The bamboo celluloses were characterised using Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). FT-IR and TGA studies confirmed the chemical treatment’s removal of hemicellulose and lignin. The FT-IR measurement demonstrated an increase in the peak intensity at 1020 cm-1, which corresponds to the vibration of the C-O-C pyranose ring, showing that the yield of isolated cellulose increased following chemical treatment. In a TGA test, bamboo celluloses were found to be thermally stable.
A preliminary study on public perceptions of hydrogen energy in Sarawak
Authors: Ahmadi E A , Ubaidillah N Z
Published: November 2022

Hydrogen energy technology is one of Malaysia’s efforts towards achieving the balance between economic progress and energy sustainability. Hence, the state of Sarawak has introduced The Sarawak Hydrogen Roadmap 2030 as one of its efforts as a hydrogen-based economy. While substantial investments were made at the technical aspects, it is important to understand the society’s perspectives in regards with the hydrogen energy. Hence, the aim of this study is to examine the public perception and acceptance of hydrogen energy in Sarawak. The data collection of this study was carried out via online questionnaire on 271 respondents. Statistical Package of Social Sciences (SPSS) was implemented to analyse the data collected, by using descriptive statistics, reliability test and multiple regression analysis. The study suggests that it is imperative to understand the society’s perception towards hydrogen energy in becoming one of the major key players in the industry.
Mass Balance and Dissolved Metal Loads in the Mamut Copper Mine Temporary Settling Pond
Authors: Isidore Feona , Cleophas Fera , Lin Chin Yik , Nainar Anand , Bidin Kawi
Published: November 2022

Mining activities which involve certain sulphide bearing minerals generally produce acid mine drainage. The understanding of the characteristics of dissolved metals before they are discharged into streams is important for environmental management. This study focuses on a small water reservoir in the former Mamut Copper Mine, known locally as the Temporary Settling Pond (TSP). The main objective of this study is to estimate the mass balance and load of dissolved metals in the acid mine drainage (from the mine pit to the TSP). Water sampling and discharge measurements were done during baseflow and high flows using water level sensors and dataloggers. The analysis of dissolved elements in water samples was done using ICP-OES, while sulphate was analysed using a ‘HACH’ spectrometer kit. Through the mass balance method, Fe had the highest removal rate followed by Cu, Al, Zn and Mn. The highest dissolved metal load discharged from the TSP was Al followed by Mn, Cu, Zn and Fe.
Assessment of Carbon Stock at Oil Palm Plantation in Klias Peninsular West Coast of Sabah
Authors: Zamri S N M , Saleh H , Rahim S Abd , Musta B
Published: November 2022

The assessment of carbon stocks in oil palm plantation were carried out in the Klias Peninsular West Coast of Sabah. The geological setting of the oil palm plantation mainly consists of Crocker Formation and Quaternary Alluvium which in mainly composed of peat soil. The peat soil from 10 sites was collected for the carbon percentage values and physico-chemical analysis. The geophysical surveys were performed to measure the thickness of peat deposits and the water table, which influenced the value of carbon stocks. The geochemical analysis of the peat soil at 0.5m depth shows an acidic pH value (3-4) and a high organic matter (30-100) %. The results of the geophysical surveys show the water table in oil palm plantation ranging from 0.3m-1.5m. Moreover, the thickness of peat as carbon storage at oil palm plantation varies from 0-6m. The bulk density obtained at selected depth varies from (0.09-0.59) g/cm3.The carbon stock in oil palm plantation is calculated around 50 tanC/ha - 900 tanC/ha. Site OP7 shows the highest carbon stock (947.73 tanC/ha) compared to site OP1 (91.33 tanC/ha). The high estimated carbon stocks resulted from a high-water table and a thick layer of organic matter.
A microbial technology approach using bioleaching for low grade metals extraction - a review
Authors: Sani S A , Haris A M
Published: November 2022

Bioleaching is a promising technological advancement of metal refinement which arises from the application of beneficial microorganism. Low grade ores and electronic waste (e-waste) that contains significant amounts of “critical metals” such as the rare earth elements (REE) are commonly discarded in waste heaps which causes major pollution. The over mining of the primary resources of REE is becoming a major concern considering its limited supply and increasing demand. Bioleaching application is able to provide not only a simpler method of metal leaching but are also cost-effective in comparison to chemical leaching and thermo-hydrometallurgy. By applying bioleaching in major e-waste treatments, we can extract back significant amounts of REE with lower cost and better environmental impacts. This review provides studies which discuss the backgrounds of bioleaching, its methods and mechanisms, direct comparison of chemical leaching, pyrometallurgy, hydrometallurgy and bioleaching in terms of its economic and environmental aspect and lastly its future in the mining industry in Malaysia.
Some mechanical characterization of the Sandakan formation’s sandstone, Sabah, Malaysia
Authors: Moneey R , Rahim I A , Musta B
Published: November 2022

This work defines the mechanical characteristics of slightly weathered sandstone belonging to sedimentary Sandakan formation in Sandakan, Sabah. The mechanical properties of uniaxial compressive strength, shear strength (includes basic and peak friction angle and cohesion) was determined by the uniaxial compressive strength test, direct shear test, tilt test and triaxial compressive strength test. The slightly weathered very fine sandstone gave higher strength but lower in basic friction angle than slightly weathered fine sandstone. The basic friction angle for very fine and fine sandstone are 28° and 33°, respectively. The value of peak friction angle and cohesion of intact rock by the triaxial compressive strength test (52-58° and 2-4 MPa) is higher than direct shear test (16-20° and 0.25-4.00 MPa) of fine sandstone rock mass (for planar surface).
Rock Endpoints and Barriers Estimation of Slope Failure in Pinousuk Gravel Slopes using Rocfall Simulation
Authors: Erfen H F W S , Musta B
Published: November 2022

The research is conducted to simulate the possibility of rock fall occurrences in the study area. The study area is located at highland area in Mesilou, Kundasang, Sabah which consists of Late Pleistocene age of tilloid deposits namely Pinousuk Gravel. Four slopes of Pinousuk Gravel were selected to estimate the distance of rock endpoints and the locations of barriers to minimize the damage when slope failure occurs by using ‘Rocfall’ simulation software. The software is commonly used for risk assessment of potential rock slope failure. The result of analysis shows the rock endpoints distance ranges from the 3.1 meters to 4.9 meters from the foot of the slope with bounce height from 0.6 meters to 2.2 meters during downfall. Based on total amount of kinetic energy on each slope, the location of the proposed barrier is within 1 meter to 4 meters from the slope foot. As a conclusion, the rock endpoints depend on slope height and angle, while the proposed location for barrier is based on its ability to withstand the kinetic energy released during slope failure.