Powered Descent Guidance via First-Order Optimization with Expansive Projection

This paper introduces a first-order method for solving optimal powered descent guidance (PDG) problems, that directly handles the nonconvex constraints associated with the maximum and minimum thrust bounds with varying mass and the pointing angle constraints on thrust vectors. This issue has been conventionally circumvented via lossless convexification (LCvx), which lifts a nonconvex feasible set to a higher-dimensional convex set, and via linear approximation of another nonconvex feasible set defined by exponential functions. However, this approach sometimes results in an infeasible solution when the solution obtained from the higher-dimensional space is projected back to the original space, especially when the problem involves a nonoptimal time of flight. Additionally, the Taylor series approximation introduces an approximation error that grows with both flight time and deviation from the reference trajectory. In this paper, we introduce a first-order approach that makes use of orthogonal projections onto nonconvex sets, allowing expansive projection (ExProj). We show that 1) this approach produces a feasible solution with better performance even for the nonoptimal time of flight cases for which conventional techniques fail to generate achievable trajectories and 2) the proposed method compensates for the linearization error that arises from Taylor series approximation, thus generating a superior guidance solution with less fuel consumption. We provide numerical examples featuring quantitative assessments to elucidate the effectiveness of the proposed methodology, particularly in terms of fuel consumption and flight time. Our analysis substantiates the assertion that the proposed approach affords enhanced flexibility in devising viable trajectories for a diverse array of planetary soft landing scenarios

The Use of Complementary and Alternative Medicine by Korean Breast Cancer Women: Is It Associated with Severity of Symptoms?

Background. Use of complementary and alternative medicine (CAM) among patients with breast cancer could be associated with severity of the cancer symptoms experienced, but there is little evidence to prove this. This study tried to investigate any difference in the severity of breast cancer symptoms between CAM users and nonusers. Methods. The study followed cross-sectional design using structured survey questionnaire. Survey participants were recruited from four different healthcare settings in Seoul, South Korea. The survey instrument comprised 39 items including questions on demographics, use of CAM, and six main symptoms associated with breast cancer and cancer treatment. Results. Out of 288 participants, 67% stated using one or more modalities of CAM. Age, education, and time duration since diagnosis of cancer were significantly associated with use of CAM. About 90% of the CAM users experienced side effects of cancer treatment. CAM users reported more severe anxiety and skin/hair changes than nonusers. Conclusions. CAM was used by those breast cancer patients who experience more severe symptoms to alleviate the conditions associated with breast cancer and cancer treatment. Our findings revealed motivation behind the CAM use, which has profound implications for clinicians to recognize patient-perceived needs

Correction to: Moth-eye Structured Polydimethylsiloxane Films for High-Efficiency Perovskite Solar Cells

In the original publication, the equal contribution information was not available in first page of the article

Recycling and Reuse of Waste Batteries from Electric Vehicles: A review

As sales of electric vehicles rapidly increase, the amount of waste batteries is also rapidly increasing. Accordingly, social interest in the recycling and reuse of waste batteries is rapidly increasing. Waste battery recycling refers to the process of reprocessing waste batteries and extracting valuable water for reuse. Reuse of waste batteries refers to the process of using them again for the same purpose after undergoing a slight conversion process. Currently, related technology development is required, and related policies are insufficient. Looking at the global trend, a waste battery collection system is being established through the labeling system and producer responsibility recycling system, battery performance and safety evaluation standards are being established, and efficient and safe transportation systems are being established. Since it is not clear who is responsible for each stage of the problem in the disposal of waste batteries, a history management system is needed. It is important to efficiently extract and recycle waste battery resources, but it is also necessary to develop battery technology free from resource scarcity. In this review, recycling and reuse-related technologies of waste batteries, battery-related policies, and rare metal replacement technologies were explored, and directions for future waste battery policies were presented

Diffusion-EDFs: Bi-equivariant Denoising Generative Modeling on SE(3) for Visual Robotic Manipulation

Diffusion generative modeling has become a promising approach for learning robotic manipulation tasks from stochastic human demonstrations. In this paper, we present Diffusion-EDFs, a novel SE(3)-equivariant diffusion-based approach for visual robotic manipulation tasks. We show that our proposed method achieves remarkable data efficiency, requiring only 5 to 10 human demonstrations for effective end-to-end training in less than an hour. Furthermore, our benchmark experiments demonstrate that our approach has superior generalizability and robustness compared to state-of-the-art methods. Lastly, we validate our methods with real hardware experiments. Project Website: https://sites.google.com/view/diffusion-edfs/homeComment: 31 pages, 13 figure

Gender-dependent difference in serum paraoxonase 1 levels of Hanwoo, Korean native cattle, and a positive association with meat quality

Objective Paraoxonase 1 (PON1), a calcium-dependent serum enzyme, has been shown to be involved in lipid metabolism. In this study, we examined the putative correlation of the serum PON1 level of Hanwoo, Korean native cattle, with gender and meat quality grade. Methods PON1 levels were estimated by determining the arylesterase and paraoxonase activities (AE and PO, respectively) in serum samples from Hanwoo individuals (n = 56). Serum PON1 levels were analyzed in different gender groups (female [n = 21], castrated male [n = 17], and male [n = 18]), and meat quality grades (≥1 [n = 23], 2 [n = 21], and 3 [n = 12]). Results Serum PON1 levels were similar in female (AE = 120±55 U/mL, PO = 84±43 mU/mL) and castrated male (123±44 U/mL, PO = 89±30 mU/mL), while male showed a significantly lower level (AE = 65±43 U/mL, PO = 44±34 mU/mL). Furthermore, analysis of serum PON1 levels in three different grades of meat quality showed similar levels in the grades ≥1 (AE = 118±49 U/mL, PO = 84±37 mU/mL) and 2 (AE = 116±54 U/mL, PO = 82±43 mU/mL), while the level was significantly lower in the grade 3 (AE = 58±35 U/mL, PO = 39±27 mU/mL) of lower meat quality. Conclusion We discovered the gender-dependent differences in serum PON1 levels of Hanwoo and a positive association of the serum PON1 level with meat quality. Results in this study suggest that PON1 would be a useful serum marker for preliminary screening of Hanwoo individuals with high-quality meat and applicable for genetic improvement

Chaperone-like protein DAY plays critical roles in photomorphogenesis.

Photomorphogenesis, light-mediated development, is an essential feature of all terrestrial plants. While chloroplast development and brassinosteroid (BR) signaling are known players in photomorphogenesis, proteins that regulate both pathways have yet to be identified. Here we report that DE-ETIOLATION IN THE DARK AND YELLOWING IN THE LIGHT (DAY), a membrane protein containing DnaJ-like domain, plays a dual-role in photomorphogenesis by stabilizing the BR receptor, BRI1, as well as a key enzyme in chlorophyll biosynthesis, POR. DAY localizes to both the endomembrane and chloroplasts via its first transmembrane domain and chloroplast transit peptide, respectively, and interacts with BRI1 and POR in their respective subcellular compartments. Using genetic analysis, we show that DAY acts independently on BR signaling and chlorophyll biogenesis. Collectively, this work uncovers DAY as a factor that simultaneously regulates BR signaling and chloroplast development, revealing a key regulator of photomorphogenesis that acts across cell compartments

A large‐scale meta‐analytic atlas of mental health problems prevalence during the COVID‐19 early pandemic

The COVID-19 pandemic and related restrictions can impact mental health. In order to quantify the mental health burden of COVID-19 pandemic, we conducted a systematic review and meta- analysis, searching World Health Organization COVID-19/PsycInfo/PubMed databases (09/29/2020), including observational studies reporting on mental health outcomes in any population affected by COVID-19. Primary outcomes were the prevalence of anxiety, depression, stress, sleep problems, post-traumatic symptoms. Sensitivity analyses were conducted on severe mental health problems, in high-quality studies, and in representative samples. Subgroup analyses were conducted stratified by age, sex, country income level, and COVID-19 infection status. One-hundred-seventy-three studies from February-July 2020 were included (n=502,261, median sample=948, age=34.4 years, females=63%). Ninety-one percent were cross-sectional studies, and 18.5%/57.2% were of high/moderate quality. Highest prevalence emerged for post-traumatic symptoms in COVID-19 infected people (94%), followed by behavioural problems in those with prior mental disorders (77%), fear in healthcare workers (71%), anxiety in caregivers/family members of people with COVID-19 (42%), general health/social contact/passive coping style in the general population (38%), depression in those with prior somatic disorders (37%), and fear in other-than-healthcare workers (29%). Females and people with COVID-19 infection had higher rates of almost all outcomes; college students/young adults of anxiety, depression, sleep problems, suicidal ideation; adults of fear and post-traumatic symptoms. Anxiety, depression, and post- traumatic symptoms were more prevalent in low-/middle-income countries, sleep problems in high-income countries. The COVID-19 pandemic adversely impacts mental health in unique manners across population subgroups. Our results inform tailored preventive strategies and interventions to mitigate current, future, and transgenerational adverse mental health of the COVID-19 pandemic

Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks

无线传感器网络，作为全球未来十大技术之一，集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术，可实时感知、采集、处理、传输网络分布区域内的各种信息数据，在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议，并针对大规模的无线传感器网络设计了一种树状路由协议，它根据节点地址信息来形成路由，从而简化了复杂繁冗的路由表查找和维护，节省了不必要的开销，提高了路由效率，实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR（AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115216

Investigating the role of infill structures on the shape memory effect of shape memory polymers in additive manufacturing

Additive Manufacturing (AM) enables designers and engineers to embed functions into printed objects by its unique advantages. This means a product, or component, which performed a specific purpose can be embedded into another part. One way of embedding functions in AM is through the use of Shape Memory Polymer (SMP). SMP is the material that reacts to a stimulus and changes shape. Using smart material's unique properties, 3D printed objects can be transformed following intended programmed sequences. Another way to embed the function into 3D printed objects is through the use of Metamaterial (also called smart structure). Metamaterial uses the smartly designed internal movement to embed function and derives unique properties from smartly designed structures. This thesis investigates the effect of infill structure on the Shape Memory Effect (SME) of SMPs. By comparing various infill structures (e.g., infill patterns and internal void), the impact on SME was explored. Previously, several studies successfully programmed SME by altering printing parameters such as infill density or filling angles. However, only limited studies were performed with Material extrusion 3D printing technology, and correlations between SME and infill structure has not fully explained yet. Therefore, this study will primarily aim to study how infill-patterns or partial parts of infill structures change SME. Various infill structures are fabricated while maintaining the same external object geometry, to explore their impact on SME. It is shown that SME can be controlled without any requirement to change materials or external geometrical parameters. This enables us to embed various SME into objects all made from the same material.Open Acces